(Slip Opinion)              OCTOBER TERM, 2016                                       1

                                       Syllabus

         NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
       being done in connection with this case, at the time the opinion is issued.
       The syllabus constitutes no part of the opinion of the Court but has been
       prepared by the Reporter of Decisions for the convenience of the reader.
       See United States v. Detroit Timber & Lumber Co., 

, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

                 PENA-RODRIGUEZ v. COLORADO

      CERTIORARI TO THE SUPREME COURT OF COLORADO

     No. 15–606.      Argued October 11, 2016—Decided March 6, 2017
A Colorado jury convicted petitioner Peña-Rodriguez of harassment and
  unlawful sexual contact. Following the discharge of the jury, two ju­
  rors told defense counsel that, during deliberations, Juror H. C. had
  expressed anti-Hispanic bias toward petitioner and petitioner’s alibi
  witness. Counsel, with the trial court’s supervision, obtained affida­
  vits from the two jurors describing a number of biased statements by
  H. C. The court acknowledged H. C.’s apparent bias but denied peti­
  tioner’s motion for a new trial on the ground that Colorado Rule of
  Evidence 606(b) generally prohibits a juror from testifying as to
  statements made during deliberations in a proceeding inquiring into
  the validity of the verdict. The Colorado Court of Appeals affirmed,
  agreeing that H. C.’s alleged statements did not fall within an excep­
  tion to Rule 606(b). The Colorado Supreme Court also affirmed, rely­
  ing on Tanner v. United States, 

, and Warger v. Shauers,
  574 U. S. ___, both of which rejected constitutional challenges to the
  federal no-impeachment rule as applied to evidence of juror miscon­
  duct or bias.
Held: Where a juror makes a clear statement indicating that he or she
 relied on racial stereotypes or animus to convict a criminal defend­
 ant, the Sixth Amendment requires that the no-impeachment rule
 give way in order to permit the trial court to consider the evidence of
 the juror’s statement and any resulting denial of the jury trial guar­
 antee. Pp. 6–21.
    (a) At common law jurors were forbidden to impeach their verdict,
 either by affidavit or live testimony. Some American jurisdictions
 adopted a more flexible version of the no-impeachment bar, known as
 the “Iowa rule,” which prevented jurors from testifying only about
 their own subjective beliefs, thoughts, or motives during delibera­
 tions. An alternative approach, later referred to as the federal ap­
2                  PENA-RODRIGUEZ v. COLORADO

                                  Syllabus

    proach, permitted an exception only for events extraneous to the de­
    liberative process. This Court’s early decisions did not establish a
    clear preference for a particular version of the no-impeachment rule,
    appearing open to the Iowa rule in United States v. Reid, 

, and Mattox v. United States, 

, but rejecting that
    approach in McDonald v. Pless, 

.
       The common-law development of the rule reached a milestone in
    1975 when Congress adopted Federal Rule of Evidence 606(b), which
    sets out a broad no-impeachment rule, with only limited exceptions.
    This version of the no-impeachment rule has substantial merit, pro­
    moting full and vigorous discussion by jurors and providing consider­
    able assurance that after being discharged they will not be sum­
    moned to recount their deliberations or otherwise harassed. The rule
    gives stability and finality to verdicts. Pp. 6–9.
       (b) Some version of the no-impeachment rule is followed in every
    State and the District of Columbia, most of which follow the Federal
    Rule. At least 16 jurisdictions have recognized an exception for juror
    testimony about racial bias in deliberations. Three Federal Courts of
    Appeals have also held or suggested there is a constitutional excep­
    tion for evidence of racial bias.
       In addressing the common-law no-impeachment rule, this Court
    noted the possibility of an exception in the “gravest and most im­
    portant cases.” United States v. 

; McDonald v.
    

. The Court has addressed the question whether
    the Constitution mandates an exception to Rule 606(b) just twice, re­
    jecting an exception each time. In Tanner, where the evidence
    showed that some jurors were under the influence of drugs and alco­
    hol during the trial, the Court identified “long-recognized and very
    substantial concerns” supporting the no-impeachment 

. The Court also outlined existing, significant safeguards
    for the defendant’s right to an impartial and competent jury beyond
    post-trial juror testimony: members of the venire can be examined for
    impartiality during voir dire; juror misconduct may be observed the
    court, counsel, and court personnel during the trial; and jurors them­
    selves can report misconduct to the court before a verdict is rendered.
    In Warger, a civil case where the evidence indicated that the jury
    forewoman failed to disclose a prodefendant bias during voir dire, the
    Court again put substantial reliance on existing safeguards for a fair
    trial. But the Court also warned, as in Reid and McDonald, that the
    no-impeachment rule may admit of exceptions for “juror bias so ex­
    treme that, almost by definition, the jury trial right has been
    abridged.” 574 U. S., at ___–___, n. 3. Reid, McDonald, and Warger
    left open the question here: whether the Constitution requires an ex­
    ception to the no-impeachment rule when a juror’s statements indi­
                    Cite as: 580 U. S. ____ (2017)                      3

                               Syllabus

cate that racial animus was a significant motivating factor in his or
her finding of guilt. Pp. 9–13.
   (c) The imperative to purge racial prejudice from the administra­
tion of justice was given new force and direction by the ratification of
the Civil War Amendments. “[T]he central purpose of the Fourteenth
Amendment was to eliminate racial discrimination emanating from
official sources in the States.” McLaughlin v. Florida, 

,
192. Time and again, this Court has enforced the Constitution’s
guarantee against state-sponsored racial discrimination in the jury
system. The Court has interpreted the Fourteenth Amendment to
prohibit the exclusion of jurors based on race, Strauder v. West Vir-
ginia, 

, 305–309; struck down laws and practices that
systematically exclude racial minorities from juries, see, e.g., Neal v.
Delaware, 

; ruled that no litigant may exclude a pro­
spective juror based on race, see, e.g., Batson v. Kentucky, 

; and held that defendants may at times be entitled to ask about
racial bias during voir dire, see, e.g., Ham v. South Carolina, 

. The unmistakable principle of these precedents is that
discrimination on the basis of race, “odious in all aspects, is especially
pernicious in the administration of justice,” Rose v. Mitchell, 

, 555, damaging “both the fact and the perception” of the ju­
ry’s role as “a vital check against the wrongful exercise of power by
the State,” Powers v. Ohio, 

, 411. Pp. 13–15.
   (d) This case lies at the intersection of the Court’s decisions endors­
ing the no-impeachment rule and those seeking to eliminate racial
bias in the jury system. Those lines of precedent need not conflict.
Racial bias, unlike the behavior in McDonald, Tanner, or Warger,
implicates unique historical, constitutional, and institutional con­
cerns and, if left unaddressed, would risk systemic injury to the ad­
ministration of justice. It is also distinct in a pragmatic sense, for the
Tanner safeguards may be less effective in rooting out racial bias.
But while all forms of improper bias pose challenges to the trial pro­
cess, there is a sound basis to treat racial bias with added precaution.
A constitutional rule that racial bias in the justice system must be
addressed—including, in some instances, after a verdict has been en­
tered—is necessary to prevent a systemic loss of confidence in jury
verdicts, a confidence that is a central premise of the Sixth Amend­
ment trial right. Pp. 15–17.
   (e) Before the no-impeachment bar can be set aside to allow further
judicial inquiry, there must be a threshold showing that one or more
jurors made statements exhibiting overt racial bias that cast serious
doubt on the fairness and impartiality of the jury’s deliberations and
resulting verdict. To qualify, the statement must tend to show that
racial animus was a significant motivating factor in the juror’s vote
4                 PENA-RODRIGUEZ v. COLORADO

                                 Syllabus

  to convict. Whether the threshold showing has been satisfied is
  committed to the substantial discretion of the trial court in light of all
  the circumstances, including the content and timing of the alleged
  statements and the reliability of the proffered evidence.
     The practical mechanics of acquiring and presenting such evidence
  will no doubt be shaped and guided by state rules of professional eth­
  ics and local court rules, both of which often limit counsel’s post-trial
  contact with jurors. The experience of those jurisdictions that have
  already recognized a racial-bias exception to the no-impeachment
  rule, and the experience of courts going forward, will inform the
  proper exercise of trial judge discretion. The Court need not address
  what procedures a trial court must follow when confronted with a
  motion for a new trial based on juror testimony of racial bias or the
  appropriate standard for determining when such evidence is suffi­
  cient to require that the verdict be set aside and a new trial be grant­
  ed. Standard and existing safeguards may also help prevent racial
  bias in jury deliberations, including careful voir dire and a trial
  court’s instructions to jurors about their duty to review the evidence,
  deliberate together, and reach a verdict in a fair and impartial way,
  free from bias of any kind. Pp. 17–21.

, reversed and remanded.

  KENNEDY, J., delivered the opinion of the Court, in which GINSBURG,
BREYER, SOTOMAYOR, and KAGAN, JJ., joined. THOMAS, J., filed a dis­
senting opinion. ALITO, J., filed a dissenting opinion, in which ROBERTS,
C. J., and THOMAS, J., joined.
                        Cite as: 580 U. S. ____ (2017)                              1

                             Opinion of the Court

     NOTICE: This opinion is subject to formal revision before publication in the
     preliminary print of the United States Reports. Readers are requested to
     notify the Reporter of Decisions, Supreme Court of the United States, Wash­
     ington, D. C. 20543, of any typographical or other formal errors, in order
     that corrections may be made before the preliminary print goes to press.


SUPREME COURT OF THE UNITED STATES
                                   _________________

                                   No. 15–606
                                   _________________


MIGUEL ANGEL PENA-RODRIGUEZ, PETITIONER v.
               COLORADO
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF 

                      COLORADO

                                 [March 6, 2017] 


   JUSTICE KENNEDY delivered the opinion of the Court.
   The jury is a central foundation of our justice system
and our democracy. Whatever its imperfections in a par­
ticular case, the jury is a necessary check on governmental
power. The jury, over the centuries, has been an inspired,
trusted, and effective instrument for resolving factual
disputes and determining ultimate questions of guilt or
innocence in criminal cases. Over the long course its
judgments find acceptance in the community, an ac­
ceptance essential to respect for the rule of law. The jury
is a tangible implementation of the principle that the law
comes from the people.
   In the era of our Nation’s founding, the right to a jury
trial already had existed and evolved for centuries,
through and alongside the common law. The jury was
considered a fundamental safeguard of individual liberty.
See The Federalist No. 83, p. 451 (B. Warner ed. 1818) (A.
Hamilton). The right to a jury trial in criminal cases was
part of the Constitution as first drawn, and it was restated
in the Sixth Amendment. Art. III, §2, cl. 3; Amdt. 6. By
operation of the Fourteenth Amendment, it is applicable to
2              PENA-RODRIGUEZ v. COLORADO

                      Opinion of the Court

the States. Duncan v. Louisiana, 

, 149–150
(1968).
   Like all human institutions, the jury system has its
flaws, yet experience shows that fair and impartial ver­
dicts can be reached if the jury follows the court’s instruc­
tions and undertakes deliberations that are honest, can­
did, robust, and based on common sense. A general rule
has evolved to give substantial protection to verdict final­
ity and to assure jurors that, once their verdict has been
entered, it will not later be called into question based on
the comments or conclusions they expressed during delib­
erations. This principle, itself centuries old, is often re­
ferred to as the no-impeachment rule. The instant case
presents the question whether there is an exception to the
no-impeachment rule when, after the jury is discharged, a
juror comes forward with compelling evidence that an-
other juror made clear and explicit statements indicating
that racial animus was a significant motivating factor in
his or her vote to convict.
                               I
   State prosecutors in Colorado brought criminal charges
against petitioner, Miguel Angel Peña-Rodriguez, based on
the following allegations. In 2007, in the bathroom of a
Colorado horse-racing facility, a man sexually assaulted
two teenage sisters. The girls told their father and identi­
fied the man as an employee of the racetrack. The police
located and arrested petitioner. Each girl separately
identified petitioner as the man who had assaulted her.
   The State charged petitioner with harassment, unlawful
sexual contact, and attempted sexual assault on a child.
Before the jury was empaneled, members of the venire
were repeatedly asked whether they believed that they
could be fair and impartial in the case. A written ques­
tionnaire asked if there was “anything about you that you
feel would make it difficult for you to be a fair juror.” App.
                 Cite as: 580 U. S. ____ (2017)            3

                     Opinion of the Court

14. The court repeated the question to the panel of pro­
spective jurors and encouraged jurors to speak in private
with the court if they had any concerns about their impar­
tiality. Defense counsel likewise asked whether anyone
felt that “this is simply not a good case” for them to be a
fair juror. 

None of the empaneled jurors ex­
pressed any reservations based on racial or any other bias.
And none asked to speak with the trial judge.
   After a 3-day trial, the jury found petitioner guilty of
unlawful sexual contact and harassment, but it failed to
reach a verdict on the attempted sexual assault charge.
When the jury was discharged, the court gave them this
instruction, as mandated by Colorado law:
    “The question may arise whether you may now dis­
    cuss this case with the lawyers, defendant, or other
    persons. For your guidance the court instructs you
    that whether you talk to anyone is entirely your own
    decision. . . . If any person persists in discussing the
    case over your objection, or becomes critical of your
    service either before or after any discussion has be­
    gun, please report it to me.” 

   Following the discharge of the jury, petitioner’s counsel
entered the jury room to discuss the trial with the jurors.
As the room was emptying, two jurors remained to speak
with counsel in private. They stated that, during delibera­
tions, another juror had expressed anti-Hispanic bias
toward petitioner and petitioner’s alibi witness. Petition­
er’s counsel reported this to the court and, with the court’s
supervision, obtained sworn affidavits from the two jurors.
   The affidavits by the two jurors described a number of
biased statements made by another juror, identified as
Juror H. C. According to the two jurors, H. C. told the
other jurors that he “believed the defendant was guilty
because, in [H. C.’s] experience as an ex-law enforcement
officer, Mexican men had a bravado that caused them to
4              PENA-RODRIGUEZ v. COLORADO

                     Opinion of the Court

believe they could do whatever they wanted with women.”

The jurors reported that H. C. stated his belief
that Mexican men are physically controlling of women
because of their sense of entitlement, and further stated,
“ ‘I think he did it because he’s Mexican and Mexican men
take whatever they want.’ ” 

According to the
jurors, H. C. further explained that, in his experience,
“nine times out of ten Mexican men were guilty of being
aggressive toward women and young girls.” 

Finally, the jurors recounted that Juror H. C. said that he
did not find petitioner’s alibi witness credible because,
among other things, the witness was “ ‘an illegal.’ ” 

witness testified during trial that he was a
legal resident of the United States.)
    After reviewing the affidavits, the trial court acknowl­
edged H. C.’s apparent bias. But the court denied peti­
tioner’s motion for a new trial, noting that “[t]he actual
deliberations that occur among the jurors are protected
from inquiry under [Colorado Rule of Evidence] 606(b).”

Like its federal counterpart, Colorado’s Rule
606(b) generally prohibits a juror from testifying as to any
statement made during deliberations in a proceeding
inquiring into the validity of the verdict. See Fed. Rule
Evid. 606(b). The Colorado Rule reads as follows:
    “(b) Inquiry into validity of verdict or indictment.
    Upon an inquiry into the validity of a verdict or indict­
    ment, a juror may not testify as to any matter or
    statement occurring during the course of the jury’s de­
    liberations or to the effect of anything upon his or any
    other juror’s mind or emotions as influencing him to
    assent to or dissent from the verdict or indictment or
    concerning his mental processes in connection there­
    with. But a juror may testify about (1) whether ex­
    traneous prejudicial information was improperly
    brought to the jurors’ attention, (2) whether any out­
                 Cite as: 580 U. S. ____ (2017)            5

                     Opinion of the Court

    side influence was improperly brought to bear upon
    any juror, or (3) whether there was a mistake in en­
    tering the verdict onto the verdict form. A juror’s affi­
    davit or evidence of any statement by the juror may
    not be received on a matter about which the juror
    would be precluded from testifying.” Colo. Rule Evid.
    606(b) (2016).
   The verdict deemed final, petitioner was sentenced to
two years’ probation and was required to register as a sex
offender. A divided panel of the Colorado Court of Appeals
affirmed petitioner’s conviction, agreeing that H. C.’s
alleged statements did not fall within an exception to Rule
606(b) and so were inadmissible to undermine the validity
of the verdict. ___ P. 3d ___, 

.
   The Colorado Supreme Court affirmed by a vote of 4 to
3. 

(2015). The prevailing opinion relied on
two decisions of this Court rejecting constitutional chal­
lenges to the federal no-impeachment rule as applied to
evidence of juror misconduct or bias. See Tanner v. United
States, 

(1987); Warger v. Shauers, 574 U. S.
___ (2014). After reviewing those precedents, the court
could find no “dividing line between different types of juror
bias or misconduct,” and thus no basis for permitting
impeachment of the verdicts in petitioner’s trial, notwith­
standing H. C.’s apparent racial 

.
This Court granted certiorari to decide whether there is a
constitutional exception to the no-impeachment rule for
instances of racial bias. 578 U. S. ___ (2016).
   Juror H. C.’s bias was based on petitioner’s Hispanic
identity, which the Court in prior cases has referred to as
ethnicity, and that may be an instructive term here. See,
e.g., Hernandez v. New York, 

, 355 (1991)
(plurality opinion). Yet we have also used the language of
race when discussing the relevant constitutional principles
in cases involving Hispanic persons. See, e.g., ibid.; Fisher
6              PENA-RODRIGUEZ v. COLORADO

                     Opinion of the Court

v. University of Tex. at Austin, 570 U. S. ___ (2013);
Rosales-Lopez v. United States, 

, 189–190
(1981) (plurality opinion). Petitioner and respondent both
refer to race, or to race and ethnicity, in this more expan­
sive sense in their briefs to the Court. This opinion refers
to the nature of the bias as racial in keeping with the
primary terminology employed by the parties and used in
our precedents.
                             II

                             A

   At common law jurors were forbidden to impeach their
verdict, either by affidavit or live testimony. This rule
originated in Vaise v. Delaval, 1 T. R. 11, 99 Eng. Rep. 944
(K. B. 1785). There, Lord Mansfield excluded juror testi­
mony that the jury had decided the case through a game of
chance. The Mansfield rule, as it came to be known, pro­
hibited jurors, after the verdict was entered, from testify­
ing either about their subjective mental processes or about
objective events that occurred during deliberations.
   American courts adopted the Mansfield rule as a matter
of common law, though not in every detail. Some jurisdic­
tions adopted a different, more flexible version of the no-
impeachment bar known as the “Iowa rule.” Under that
rule, jurors were prevented only from testifying about
their own subjective beliefs, thoughts, or motives during
deliberations. See Wright v. Illinois & Miss. Tel. Co., 

(1866). Jurors could, however, testify about
objective facts and events occurring during deliberations,
in part because other jurors could corroborate that
testimony.
   An alternative approach, later referred to as the federal
approach, stayed closer to the original Mansfield rule. See

, at ___ (slip op., at 5). Under this version of
the rule, the no-impeachment bar permitted an exception
only for testimony about events extraneous to the deliber­
                 Cite as: 580 U. S. ____ (2017)           7

                     Opinion of the Court

ative process, such as reliance on outside evidence—
newspapers, dictionaries, and the like—or personal inves­
tigation of the facts.
   This Court’s early decisions did not establish a clear
preference for a particular version of the no-impeachment
rule. In United States v. Reid, 

(1852), the
Court appeared open to the admission of juror testimony
that the jurors had consulted newspapers during delibera­
tions, but in the end it barred the evidence because the
newspapers “had not the slightest influence” on the ver­
dict. 

The Reid Court warned that juror testi­
mony “ought always to be received with great caution.”

an important admonition: “cases might
arise in which it would be impossible to refuse” juror
testimony “without violating the plainest principles of
justice.” 

case the Court required the admission of
juror affidavits stating that the jury consulted information
that was not in evidence, including a prejudicial news-
paper article. Mattox v. United States, 

, 151
(1892). The Court suggested, furthermore, that the ad­
mission of juror testimony might be governed by a more
flexible rule, one permitting jury testimony even where it
did not involve consultation of prejudicial extraneous
information. 

see also Hyde v. United
States, 

, 382–384 (1912) (stating that the
more flexible Iowa rule “should apply,” but excluding
evidence that the jury reached the verdict by trading
certain defendants’ acquittals for others’ convictions).
   Later, however, the Court rejected the more lenient
Iowa rule. In McDonald v. Pless, 

(1915), the
Court affirmed the exclusion of juror testimony about
objective events in the jury room. There, the jury allegedly
had calculated a damages award by averaging the
numerical submissions of each member. 

As the Court explained, admitting that evidence would
8             PENA-RODRIGUEZ v. COLORADO

                     Opinion of the Court

have “dangerous consequences”: “no verdict would be safe”
and the practice would “open the door to the most perni­
cious arts and tampering with jurors.” 

(inter­
nal quotation marks omitted). Yet the Court reiterated its
admonition from Reid, again cautioning that the no-
impeachment rule might recognize exceptions “in the
gravest and most important cases” where exclusion of
juror affidavits might well violate “the plainest principles
of 

(quoting 

;
internal quotation marks omitted).
   The common-law development of the no-impeachment
rule reached a milestone in 1975, when Congress adopted
the Federal Rules of Evidence, including Rule 606(b).
Congress, like the McDonald Court, rejected the Iowa
rule. Instead it endorsed a broad no-impeachment rule,
with only limited exceptions.
  The version of the rule that Congress adopted was “no
accident.” Warger, 574 U. S., at ___ (slip op., at 7). The
Advisory Committee at first drafted a rule reflecting the
Iowa approach, prohibiting admission of juror testimony
only as it related to jurors’ mental processes in reaching a
verdict. The Department of Justice, however, expressed
concern over the preliminary rule. The Advisory Commit­
tee then drafted the more stringent version now in effect,
prohibiting all juror testimony, with exceptions only where
the jury had considered prejudicial extraneous evidence or
was subject to other outside influence. Rules of Evidence
for United States Courts and Magistrates, 56 F. R. D. 183,
265 (1972). The Court adopted this second version and
transmitted it to Congress.
  The House favored the Iowa approach, but the Senate
expressed concern that it did not sufficiently address the
public policy interest in the finality of verdicts. S. Rep.
No. 93–1277, pp. 13–14 (1974). Siding with the Senate,
the Conference Committee adopted, Congress enacted, and
the President signed the Court’s proposed rule. The sub­
                 Cite as: 580 U. S. ____ (2017)            9

                     Opinion of the Court

stance of the Rule has not changed since 1975, except for a
2006 modification permitting evidence of a clerical mis­
take on the verdict form. See 574 U. S., at ___.
  The current version of Rule 606(b) states as follows:
    “(1) Prohibited Testimony or Other Evidence. During
    an inquiry into the validity of a verdict or indictment,
    a juror may not testify about any statement made or
    incident that occurred during the jury’s deliberations;
    the effect of anything on that juror’s or another juror’s
    vote; or any juror’s mental processes concerning the
    verdict or indictment. The court may not receive a ju­
    ror’s affidavit or evidence of a juror’s statement on
    these matters.
    “(2) Exceptions. A juror may testify about whether:
      “(A) extraneous prejudicial information was im­
    properly brought to the jury’s attention;
      “(B) an outside influence was improperly brought to
    bear on any juror; or
      “(C) a mistake was made in entering the verdict on
    the verdict form.”
  This version of the no-impeachment rule has substantial
merit. It promotes full and vigorous discussion by provid­
ing jurors with considerable assurance that after being
discharged they will not be summoned to recount their
deliberations, and they will not otherwise be harassed or
annoyed by litigants seeking to challenge the verdict. The
rule gives stability and finality to verdicts.
                             B
  Some version of the no-impeachment rule is followed in
every State and the District of Columbia. Variations
make classification imprecise, but, as a general matter, it
appears that 42 jurisdictions follow the Federal Rule,
while 9 follow the Iowa Rule. Within both classifications
there is a diversity of approaches. Nine jurisdictions that
10            PENA-RODRIGUEZ v. COLORADO

                     Opinion of the Court

follow the Federal Rule have codified exceptions other
than those listed in Federal Rule 606(b). See Appendix,
infra. At least 16 jurisdictions, 11 of which follow the
Federal Rule, have recognized an exception to the no-
impeachment bar under the circumstances the Court faces
here: juror testimony that racial bias played a part in
deliberations. 

parties and amici,
only one State other than Colorado has addressed this
issue and declined to recognize an exception for racial
bias. See Commonwealth v. Steele, 

, 377–379,

, 807–808 (2012).
   The federal courts, for their part, are governed by Fed­
eral Rule 606(b), but their interpretations deserve further
comment. Various Courts of Appeals have had occasion to
consider a racial bias exception and have reached different
conclusions. Three have held or suggested there is a
constitutional exception for evidence of racial bias. See
United States v. Villar, 

, 87–88 (CA1 2009)
(holding the Constitution demands a racial-bias excep­
tion); United States v. Henley, 

, 1119–1121
(CA9 2001) (finding persuasive arguments in favor of an
exception but not deciding the issue); Shillcutt v. Gagnon,

, 1158–1160 (CA7 1987) (observing that in
some cases fundamental fairness could require an excep­
tion). One Court of Appeals has declined to find an excep­
tion, reasoning that other safeguards inherent in the trial
process suffice to protect defendants’ constitutional inter­
ests. See United States v. Benally, 

, 1240–
1241 (CA10 2008). Another has suggested as much, hold­
ing in the habeas context that an exception for racial bias
was not clearly established but indicating in dicta that no
such exception exists. See Williams v. Price, 

, 237–239 (CA3 2003) (Alito, J.). And one Court of
Appeals has held that evidence of racial bias is excluded
by Rule 606(b), without addressing whether the Constitu­
tion may at times demand an exception. See Martinez v.
                  Cite as: 580 U. S. ____ (2017)            11

                      Opinion of the Court

Food City, Inc., 

, 373–374 (CA5 1981).
                                C
   In addressing the scope of the common-law no-
impeachment rule before Rule 606(b)’s adoption, the Reid
and McDonald Courts noted the possibility of an exception
to the rule in the “gravest and most important cases.”

; 

. Yet
since the enactment of Rule 606(b), the Court has ad­
dressed the precise question whether the Constitution
mandates an exception to it in just two instances.
   In its first case, Tanner, 

, the Court rejected
a Sixth Amendment exception for evidence that some
jurors were under the influence of drugs and alcohol dur­
ing the trial. 

Central to the Court’s reasoning
were the “long-recognized and very substantial concerns”
supporting “the protection of jury deliberations from in­
trusive inquiry.” 

The Tanner Court echoed
McDonald’s concern that, if attorneys could use juror
testimony to attack verdicts, jurors would be “harassed
and beset by the defeated party,” thus destroying “all
frankness and freedom of discussion and 

(quoting 

–268). The
Court was concerned, moreover, that attempts to impeach
a verdict would “disrupt the finality of the process” and
undermine both “jurors’ willingness to return an unpopu­
lar verdict” and “the community’s trust in a system that
relies on the decisions of 

–
121.
   The Tanner Court outlined existing, significant safe­
guards for the defendant’s right to an impartial and com­
petent jury beyond post-trial juror testimony. At the
outset of the trial process, voir dire provides an opportun-
ity for the court and counsel to examine members of the
venire for impartiality. As a trial proceeds, the court,
counsel, and court personnel have some opportunity to
12             PENA-RODRIGUEZ v. COLORADO

                     Opinion of the Court

learn of any juror misconduct. And, before the verdict,
jurors themselves can report misconduct to the court.
These procedures do not undermine the stability of a
verdict once rendered. Even after the trial, evidence of
misconduct other than juror testimony can be used to
attempt to impeach the verdict. 

Balancing
these interests and safeguards against the defendant’s
Sixth Amendment interest in that case, the Court affirmed
the exclusion of affidavits pertaining to the jury’s inebri­
ated state. 

to consider the general issue presented
here was Warger, 574 U. S. ___. The Court again rejected
the argument that, in the circumstances there, the jury
trial right required an exception to the no-impeachment
rule. Warger involved a civil case where, after the verdict
was entered, the losing party sought to proffer evidence
that the jury forewoman had failed to disclose prodefend­
ant bias during voir dire. As in Tanner, the Court put
substantial reliance on existing safeguards for a fair trial.
The Court stated: “Even if jurors lie in voir dire in a way
that conceals bias, juror impartiality is adequately as­
sured by the parties’ ability to bring to the court’s atten­
tion any evidence of bias before the verdict is rendered,
and to employ nonjuror evidence even after the verdict is
rendered.” 574 U. S., at ___ (slip op., at 10).
   In Warger, however, the Court did reiterate that the no-
impeachment rule may admit exceptions. As in Reid and
McDonald, the Court warned of “juror bias so extreme
that, almost by definition, the jury trial right has been
abridged.” 574 U. S., at ___–___, n. 3 (slip op., at 10–11,
n. 3). “If and when such a case arises,” the Court indicated
it would “consider whether the usual safeguards are or
are not sufficient to protect the integrity of the process.”

Warger that there may be extreme
cases where the jury trial right requires an exception to
                 Cite as: 580 U. S. ____ (2017)          13

                     Opinion of the Court

the no-impeachment rule must be interpreted in context
as a guarded, cautious statement. This caution is war­
ranted to avoid formulating an exception that might un­
dermine the jury dynamics and finality interests the no-
impeachment rule seeks to protect. Today, however, the
Court faces the question that Reid, McDonald, and Warger
left open. The Court must decide whether the Constitu­
tion requires an exception to the no-impeachment rule
when a juror’s statements indicate that racial animus was
a significant motivating factor in his or her finding of
guilt.
                              III
   It must become the heritage of our Nation to rise above
racial classifications that are so inconsistent with our
commitment to the equal dignity of all persons. This
imperative to purge racial prejudice from the administra­
tion of justice was given new force and direction by the
ratification of the Civil War Amendments.
   “[T]he central purpose of the Fourteenth Amendment
was to eliminate racial discrimination emanating from
official sources in the States.” McLaughlin v. Florida, 

, 192 (1964). In the years before and after the
ratification of the Fourteenth Amendment, it became clear
that racial discrimination in the jury system posed a
particular threat both to the promise of the Amendment
and to the integrity of the jury trial. “Almost immediately
after the Civil War, the South began a practice that would
continue for many decades: All-white juries punished
black defendants particularly harshly, while simultane­
ously refusing to punish violence by whites, including Ku
Klux Klan members, against blacks and Republicans.”
Forman, Juries and Race in the Nineteenth Century, 113
Yale L. J. 895, 909–910 (2004). To take one example, just
in the years 1865 and 1866, all-white juries in Texas
decided a total of 500 prosecutions of white defendants
14            PENA-RODRIGUEZ v. COLORADO

                     Opinion of the Court

charged with killing African-Americans. All 500 were
acquitted. 

The stark and unapologetic nature
of race-motivated outcomes challenged the American belief
that “the jury was a bulwark of liberty,” 

and
prompted Congress to pass legislation to integrate the jury
system and to bar persons from eligibility for jury service
if they had conspired to deny the civil rights of African-
Americans, 

Members of Congress stressed
that the legislation was necessary to preserve the right to
a fair trial and to guarantee the equal protection of the
laws. 

confront racial animus in the justice system
is not the legislature’s alone. Time and again, this Court
has been called upon to enforce the Constitution’s guaran­
tee against state-sponsored racial discrimination in the
jury system. Beginning in 1880, the Court interpreted the
Fourteenth Amendment to prohibit the exclusion of jurors
on the basis of race. Strauder v. West Virginia, 

, 305–309 (1880). The Court has repeatedly struck
down laws and practices that systematically exclude racial
minorities from juries. See, e.g., Neal v. Delaware, 

(1881); Hollins v. Oklahoma, 

(1935) (per curiam); Avery v. Georgia, 

(1953);
Hernandez v. Texas, 

(1954); Castaneda v.
Partida, 

(1977). To guard against discrimi­
nation in jury selection, the Court has ruled that no liti­
gant may exclude a prospective juror on the basis of race.
Batson v. Kentucky, 

(1986); Edmonson v.
Leesville Concrete Co., 

(1991); Georgia v.
McCollum, 

(1992). In an effort to ensure that
individuals who sit on juries are free of racial bias, the
Court has held that the Constitution at times demands
that defendants be permitted to ask questions about racial
bias during voir dire. Ham v. South Carolina, 

(1973); Rosales-Lopez, 

; Turner v. Mur-
ray, 

(1986).
                  Cite as: 580 U. S. ____ (2017)           15

                      Opinion of the Court

   The unmistakable principle underlying these precedents
is that discrimination on the basis of race, “odious in all
aspects, is especially pernicious in the administration of
justice.” Rose v. Mitchell, 

, 555 (1979). The
jury is to be “a criminal defendant’s fundamental ‘protec­
tion of life and liberty against race or color prejudice.’ ”
McCleskey v. Kemp, 

, 310 (1987) (quoting

). Permitting racial prejudice in
the jury system damages “both the fact and the percep­
tion” of the jury’s role as “a vital check against the wrong­
ful exercise of power by the State.” Powers v. Ohio, 

, 411 (1991); cf. Aldridge v. United States, 

, 315 (1931); Buck v. Davis, ante, at 22.
                              IV 

                               A

   This case lies at the intersection of the Court’s decisions
endorsing the no-impeachment rule and its decisions
seeking to eliminate racial bias in the jury system. The
two lines of precedent, however, need not conflict.
   Racial bias of the kind alleged in this case differs in
critical ways from the compromise verdict in McDonald,
the drug and alcohol abuse in Tanner, or the pro-
defendant bias in Warger. The behavior in those cases is
troubling and unacceptable, but each involved anomalous
behavior from a single jury—or juror—gone off course.
Jurors are presumed to follow their oath, cf. Penry v.
Johnson, 

, 799 (2001), and neither history
nor common experience show that the jury system is rife
with mischief of these or similar kinds. To attempt to rid
the jury of every irregularity of this sort would be to ex­
pose it to unrelenting scrutiny. “It is not at all clear . . .
that the jury system could survive such efforts to perfect
it.” 

.
   The same cannot be said about racial bias, a familiar
and recurring evil that, if left unaddressed, would risk
16            PENA-RODRIGUEZ v. COLORADO

                     Opinion of the Court

systemic injury to the administration of justice. This
Court’s decisions demonstrate that racial bias implicates
unique historical, constitutional, and institutional con­
cerns. An effort to address the most grave and serious
statements of racial bias is not an effort to perfect the
jury but to ensure that our legal system remains capable
of coming ever closer to the promise of equal treat­
ment under the law that is so central to a functioning
democracy.
  Racial bias is distinct in a pragmatic sense as well. In
past cases this Court has relied on other safeguards to
protect the right to an impartial jury. Some of those safe­
guards, to be sure, can disclose racial bias. Voir dire at
the outset of trial, observation of juror demeanor and
conduct during trial, juror reports before the verdict, and
nonjuror evidence after trial are important mechanisms
for discovering bias. Yet their operation may be compro­
mised, or they may prove insufficient. For instance, this
Court has noted the dilemma faced by trial court judges
and counsel in deciding whether to explore potential racial
bias at voir dire. See Rosales-Lopez, supra; Ristaino v.
Ross, 

(1976). Generic questions about juror
impartiality may not expose specific attitudes or biases
that can poison jury deliberations. Yet more pointed
questions “could well exacerbate whatever prejudice might
exist without substantially aiding in exposing it.” Rosales-

(Rehnquist, J., concurring in result).
  The stigma that attends racial bias may make it diffi­
cult for a juror to report inappropriate statements during
the course of juror deliberations. It is one thing to accuse
a fellow juror of having a personal experience that im­
properly influences her consideration of the case, as would
have been required in Warger. It is quite another to call
her a bigot.
  The recognition that certain of the Tanner safeguards
may be less effective in rooting out racial bias than other
                  Cite as: 580 U. S. ____ (2017)           17

                      Opinion of the Court

kinds of bias is not dispositive. All forms of improper bias
pose challenges to the trial process. But there is a sound
basis to treat racial bias with added precaution. A consti­
tutional rule that racial bias in the justice system must be
addressed—including, in some instances, after the verdict
has been entered—is necessary to prevent a systemic loss
of confidence in jury verdicts, a confidence that is a central
premise of the Sixth Amendment trial right.
                               B
   For the reasons explained above, the Court now holds
that where a juror makes a clear statement that indicates
he or she relied on racial stereotypes or animus to convict
a criminal defendant, the Sixth Amendment requires that
the no-impeachment rule give way in order to permit the
trial court to consider the evidence of the juror’s statement
and any resulting denial of the jury trial guarantee.
   Not every offhand comment indicating racial bias or
hostility will justify setting aside the no-impeachment bar
to allow further judicial inquiry. For the inquiry to pro­
ceed, there must be a showing that one or more jurors
made statements exhibiting overt racial bias that cast
serious doubt on the fairness and impartiality of the jury’s
deliberations and resulting verdict. To qualify, the state­
ment must tend to show that racial animus was a signifi­
cant motivating factor in the juror’s vote to convict.
Whether that threshold showing has been satisfied is a
matter committed to the substantial discretion of the trial
court in light of all the circumstances, including the con­
tent and timing of the alleged statements and the reliabil­
ity of the proffered evidence.
   The practical mechanics of acquiring and presenting
such evidence will no doubt be shaped and guided by state
rules of professional ethics and local court rules, both of
which often limit counsel’s post-trial contact with jurors.
See 27 C. Wright & V. Gold, Federal Practice and Proce­
18             PENA-RODRIGUEZ v. COLORADO

                      Opinion of the Court

dure: Evidence §6076, pp. 580–583 (2d ed. 2007) (Wright);
see also Variations of ABA Model Rules of Professional
Conduct, Rule 3.5 (Sept. 15, 2016) (overview of state ethics
rules); 2 Jurywork Systematic Techniques §13:18 (2016–
2017) (overview of Federal District Court rules). These
limits seek to provide jurors some protection when they
return to their daily affairs after the verdict has been
entered. But while a juror can always tell counsel they do
not wish to discuss the case, jurors in some instances may
come forward of their own accord.
   That is what happened here. In this case the alleged
statements by a juror were egregious and unmistakable in
their reliance on racial bias. Not only did juror H. C.
deploy a dangerous racial stereotype to conclude petitioner
was guilty and his alibi witness should not be believed,
but he also encouraged other jurors to join him in convict­
ing on that basis.
   Petitioner’s counsel did not seek out the two jurors’
allegations of racial bias. Pursuant to Colorado’s manda­
tory jury instruction, the trial court had set limits on juror
contact and encouraged jurors to inform the court if any­
one harassed them about their role in the case. Similar
limits on juror contact can be found in other jurisdictions
that recognize a racial-bias exception. See, e.g., Fla.
Standard Jury Instrs. in Crim. Cases No. 4.2 (West 2016)
(“Although you are at liberty to speak with anyone about
your deliberations, you are also at liberty to refuse to
speak to anyone”); Mass. Office of Jury Comm’r, Trial
Juror’s Handbook (Dec. 2015) (“You are not required to
speak with anyone once the trial is over. . . . If anyone
tries to learn this confidential information from you, or if
you feel harassed or embarrassed in any way, you should
report it to the court . . . immediately”); N. J. Crim. Model
Jury Charges, Non 2C Charges, Dismissal of Jury (2014)
(“It will be up to each of you to decide whether to speak
about your service as a juror”).
                 Cite as: 580 U. S. ____ (2017)          19

                     Opinion of the Court

   With the understanding that they were under no obliga­
tion to speak out, the jurors approached petitioner’s coun­
sel, within a short time after the verdict, to relay their
concerns about H. C.’s statements. App. 77. A similar
pattern is common in cases involving juror allegations of
racial bias. See, e.g., 

( juror e­
mailed defense counsel within hours of the verdict); Kittle
v. United States, 

, 1147 (D. C. 2013) ( juror
wrote a letter to the judge the same day the court dis­
charged the jury); 

( juror ap­
proached defense counsel the day after the jury announced
its verdict). Pursuant to local court rules, petitioner’s
counsel then sought and received permission from the
court to contact the two jurors and obtain affidavits lim­
ited to recounting the exact statements made by H. C. that
exhibited racial bias.
   While the trial court concluded that Colorado’s Rule
606(b) did not permit it even to consider the resulting
affidavits, the Court’s holding today removes that bar.
When jurors disclose an instance of racial bias as serious
as the one involved in this case, the law must not wholly
disregard its occurrence.
                               C
   As the preceding discussion makes clear, the Court
relies on the experiences of the 17 jurisdictions that have
recognized a racial-bias exception to the no-impeachment
rule—some for over half a century—with no signs of an
increase in juror harassment or a loss of juror willingness
to engage in searching and candid deliberations.
   The experience of these jurisdictions, and the experience
of the courts going forward, will inform the proper exercise
of trial judge discretion in these and related matters. This
case does not ask, and the Court need not address, what
procedures a trial court must follow when confronted with
a motion for a new trial based on juror testimony of racial
20             PENA-RODRIGUEZ v. COLORADO

                     Opinion of the Court

bias. See 27 Wright 575–578 (noting a divergence of
authority over the necessity and scope of an evidentiary
hearing on alleged juror misconduct). The Court also does
not decide the appropriate standard for determining when
evidence of racial bias is sufficient to require that the
verdict be set aside and a new trial be granted. Compare,
e.g., 

(inquiring whether racial
bias “pervaded the jury room”), with, e.g., 

(“One racist juror would be enough”).
                               D
   It is proper to observe as well that there are standard
and existing processes designed to prevent racial bias in
jury deliberations. The advantages of careful voir dire
have already been noted. And other safeguards deserve
mention.
   Trial courts, often at the outset of the case and again in
their final jury instructions, explain the jurors’ duty to
review the evidence and reach a verdict in a fair and
impartial way, free from bias of any kind. Some instruc­
tions are framed by trial judges based on their own learn­
ing and experience. Model jury instructions likely take
into account these continuing developments and are com­
mon across jurisdictions. See, e.g., 1A K. O’Malley, J.
Grenig, & W. Lee, Federal Jury Practice and Instructions,
Criminal §10:01, p. 22 (6th ed. 2008) (“Perform these
duties fairly. Do not let any bias, sympathy or prejudice
that you may feel toward one side or the other influence
your decision in any way”). Instructions may emphasize
the group dynamic of deliberations by urging jurors to
share their questions and conclusions with their col­
leagues. See, e.g., 

841 (“It is your duty as
jurors to consult with one another and to deliberate with
one another with a view towards reaching an agreement if
you can do so without violence to individual judgment”).
   Probing and thoughtful deliberation improves the likeli­
                 Cite as: 580 U. S. ____ (2017)          21

                     Opinion of the Court

hood that other jurors can confront the flawed nature of
reasoning that is prompted or influenced by improper
biases, whether racial or otherwise. These dynamics can
help ensure that the exception is limited to rare cases.
                        *     *     *
   The Nation must continue to make strides to overcome
race-based discrimination. The progress that has already
been made underlies the Court’s insistence that blatant
racial prejudice is antithetical to the functioning of the
jury system and must be confronted in egregious cases like
this one despite the general bar of the no-impeachment
rule. It is the mark of a maturing legal system that it
seeks to understand and to implement the lessons of
history. The Court now seeks to strengthen the broader
principle that society can and must move forward by
achieving the thoughtful, rational dialogue at the founda­
tion of both the jury system and the free society that
sustains our Constitution.
   The judgment of the Supreme Court of Colorado is
reversed, and the case is remanded for further proceedings
not inconsistent with this opinion.
                                           It is so ordered.
22             PENA-RODRIGUEZ v. COLORADO

                     Opinion
                Appendix      of the of
                         to opinion  Court
                                        the Court


                         APPENDIX

  Codified Exceptions in Addition to Those Enumerated in
                    Fed. Rule Evid. 606(b)
   See Ariz. Rules Crim. Proc. 24.1(c)(3), (d) (2011) (excep­
tion for evidence of misconduct, including verdict by game
of chance or intoxication); Idaho Rule Evid. 606(b) (2016)
(game of chance); Ind. Rule Evid. 606(b)(2)(A) (Burns
2014) (drug or alcohol use); Minn. Rule Evid. 606(b) (2014)
(threats of violence or violent acts); Mont. Rule Evid.
606(b) (2015) (game of chance); N. D. Rule Evid.
606(b)(2)(C) (2016–2017) (same); Tenn. Rule Evid. 606(b)
(2016) (quotient verdict or game of chance); Tex. Rule
Evid. 606(b)(2)(B) (West 2016) (rebutting claim juror was
unqualified); Vt. Rule Evid. 606(b) (Cum. Supp. 2016)
(juror communication with nonjuror); see also 27 C.
Wright & V. Gold, Federal Practice and Procedure: Evi­
dence §6071, p. 447, and n. 66 (2d ed. 2007); 

and n. 70; 

and n. 72.

 Judicially Recognized Exceptions for Evidence of Racial
                         Bias

   See State v. Santiago, 

, 323–340, 

1, 14–22 (1998); Kittle v. United States, 

,
1154–1556 (D. C. 2013); Fisher v. State, 

,
919–921, and n. 4 (Del. 1996) (Appendix to opinion), Pow-
ell v. Allstate Ins. Co., 

, 357–358 (Fla. 1995);
Spencer v. State, 

, 643–644, 

,
184–185 (1990); State v. Jackson, 

, 48–49, 

, 80–81 (1996); Commonwealth v. Laguer, 

, 97–98, 

, 376 (1991); State v.
Callender, 

, 746 (Minn. 1980); Fleshner v.
Pepose Vision Inst., P. C., 

, 87–90 (Mo.
                 Cite as: 580 U. S. ____ (2017)           23

                     Opinion
                Appendix      of the of
                         to opinion  Court
                                        the Court

2010); State v. Levitt, 36 N. J. 266, 271–273, 

,
467–468 (1961); People v. Rukaj, 

277,
280–281, 506 N. Y. S. 2d 677, 679–680 (1986); State v.
Hidanovic, 

, ¶¶21–26, 

, 472–
474; State v. Brown, 

, 1110 (R. I. 2013); State
v. Hunter, 320 S. C. 85, 88, 

, 316 (1995);
Seattle v. Jackson, 

, 738, 

,
389 (1967); After Hour Welding, Inc. v. Laneil Manage-
ment Co., 

, 739–740, 

, 690
(1982).
                  Cite as: 580 U. S. ____ (2017)            1

                     THOMAS, J., dissenting

SUPREME COURT OF THE UNITED STATES
                          _________________

                           No. 15–606
                          _________________


MIGUEL ANGEL PENA-RODRIGUEZ, PETITIONER v.
               COLORADO
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF 

                      COLORADO

                         [March 6, 2017] 


  JUSTICE THOMAS, dissenting.
  The Court today holds that the Sixth Amendment re-
quires the States to provide a criminal defendant the
opportunity to impeach a jury’s guilty verdict with juror
testimony about a juror’s alleged racial bias, notwith-
standing a state procedural rule forbidding such testi-
mony. I agree with JUSTICE ALITO that the Court’s decision
is incompatible with the text of the Amendment it pur-
ports to interpret and with our precedents. I write sepa-
rately to explain that the Court’s holding also cannot be
squared with the original understanding of the Sixth or
Fourteenth Amendments.
                              I
   The Sixth Amendment’s protection of the right, “[i]n all
criminal prosecutions,” to a “trial, by an impartial jury,” is
limited to the protections that existed at common law
when the Amendment was ratified. See, e.g., Apprendi v.
New Jersey, 

, 500, and n. 1 (2000) (THOMAS,
J., concurring); 3 J. Story, Commentaries on the Constitu-
tion of the United States §1773, pp. 652–653 (1833) (Story)
(explaining that “the trial by jury in criminal cases” pro-
tected by the Constitution is the same “great privilege”
that was “a part of that admirable common law” of Eng-
land); cf. 5 St. G. Tucker, Blackstone’s Commentaries 349,
2             PENA-RODRIGUEZ v. COLORADO

                    THOMAS, J., dissenting

n. 2 (1803). It is therefore “entirely proper to look to the
common law” to ascertain whether the Sixth Amendment
requires the result the Court today reaches. 

, n. 1.
   The Sixth Amendment’s specific guarantee of impartial-
ity incorporates the common-law understanding of that
term. See, e.g., 3 W. Blackstone, Commentaries on the
Laws of England 365 (1769) (Blackstone) (describing
English trials as “impartially just” because of their “cau-
tion against all partiality and bias” in the jury). The
common law required a juror to have “freedome of mind”
and to be “indifferent as hee stands unsworne.” 1 E. Coke,
First Part of the Institutes of the Laws of England §234, p.
155a (16th ed. 1809); accord, 3 M. Bacon, A New Abridg-
ment of the Law 258 (3d ed. 1768); cf. T. Cooley, A Trea-
tise on the Constitutional Limitations Which Rest Upon
the Legislative Power of the States of the American Union
319 (1868) (“The jury must be indifferent between the
prisoner and the commonwealth”). Impartial jurors could
“have no interest of their own affected, and no personal
bias, or pre-possession, in favor [of] or against either
party.” Pettis v. Warren, 

, 427 (Conn. Super.
1788).
                             II
  The common-law right to a jury trial did not, however,
guarantee a defendant the right to impeach a jury verdict
with juror testimony about juror misconduct, including “a
principal species of [juror] misbehaviour”—“notorious
partiality.” 3 Blackstone 388. Although partiality was a
ground for setting aside a jury verdict, ibid., the English
common-law rule at the time the Sixth Amendment was
ratified did not allow jurors to supply evidence of that
misconduct. In 1770, Lord Mansfield refused to receive a
juror’s affidavit to impeach a verdict, declaring that such
an affidavit “can’t be read.” Rex v. Almon, 5 Burr. 2687,
                     Cite as: 580 U. S. ____ (2017)                   3

                        THOMAS, J., dissenting

98 Eng. Rep. 411 (K. B.). And in 1785, Lord Mansfield
solidified the doctrine, holding that “[t]he Court [could not]
receive such an affidavit from any of the jurymen” to prove
that the jury had cast lots to reach a verdict. Vaise v.
Delaval, 1 T. R. 11, 99 Eng. Rep. 944 (K. B.).1
  At the time of the founding, the States took mixed ap-
proaches to this issue. See Cluggage v. Swan, 

,
156 (Pa. 1811) (opinion of Yeates, J.) (“The opinions of
American judges . . . have greatly differed on the point in
question”); Bishop v. Georgia, 

, 126 (1850) (de-
scribing the common law in 1776 on this question as “in a
transition state”). Many States followed Lord Mansfield’s
no-impeachment rule and refused to receive juror affida-
vits. See, e.g., Brewster v. Thompson, 1 N. J. L. 32 (1790)
(per curiam); Robbins v. Windover, 

, 14 (Vt. 1802);
Taylor v. Giger, 

, 597–598 (1808); Price v.
McIlvain, 

, 504 (S. C. 1815); Tyler v. Stevens,
4 N. H. 116, 117 (1827); 1 Z. Swift, A Digest of the Laws of
the State of Connecticut 775 (1822) (“In England, and in
the courts of the United States, jurors are not permitted to
be witnesses respecting the misconduct of the jury . . . and
this is, most unquestionably, the correct principle”). Some
States, however, permitted juror affidavits about juror
misconduct. See, e.g., Crawford v. State, 

, 68
(1821); Cochran v. Street, 

, 81 (1792). And others
initially permitted such evidence but quickly reversed
course. Compare, e.g., Smith v. Cheetham, 

,
——————
  1 Prior to 1770, it appears that juror affidavits were sometimes re-

ceived to impeach a verdict on the ground of juror misbehavior, al-
though only “with great caution.” McDonald v. Pless, 

, 268
(1915); see, e.g., Dent v. The Hundred of Hertford, 2 Salk. 645, 91 Eng.
Rep. 546 (K. B. 1696); Philips v. Fowler, Barnes. 441, 94 Eng. Rep. 994
(K. B. 1735). But “previous to our Revolution, and at least as early as
1770, the doctrine in England was distinctly ruled the other way, and
has so stood ever since.” 3 T. Waterman, A Treatise on the Principles of
Law and Equity Which Govern Courts in the Granting of New Trials in
Cases Civil and Criminal 1429 (1855).
4             PENA-RODRIGUEZ v. COLORADO

                    THOMAS, J., dissenting

59–60 (N. Y. 1805) (opinion of Livingston, J.) (permitting
juror testimony), with Dana v. Tucker, 

, 488–
489 (N. Y. 1809) (per curiam) (overturning Cheetham);
compare also Bradley’s Lessee v. Bradley, 4 Dall. 112 (Pa.
1792) (permitting juror affidavits), with, e.g., 

–158 (opinion of Yeates, J.) (explaining that
Bradley was incorrectly reported and rejecting affidavits);
compare also Talmadge v. Northrop, 

(Conn.
1793) (admitting juror testimony), with State v. Freeman,

, 350–352 (1824) (“The opinion of almost
the whole legal world is adverse to the reception of the
testimony in question; and, in my opinion, on invincible
foundations”).
  By the time the Fourteenth Amendment was ratified,
Lord Mansfield’s no-impeachment rule had become firmly
entrenched in American law. See Lettow, New Trial for
Verdict Against Law: Judge-Jury Relations in Early-
Nineteenth Century America, 71 Notre Dame L. Rev. 505,
536 (1996) (“[O]pponents of juror affidavits had largely
won out by the middle of the century”); 8 J. Wigmore,
Evidence in Trials at Common Law §2352, p. 697 (J.
McNaughton rev. 1961) (Wigmore) (Lord Mansfield’s rule
“came to receive in the United States an adherence almost
unquestioned”); J. Proffatt, A Treatise on Trial by Jury
§408, p. 467 (1877) (“It is a well established rule of law
that no affidavit shall be received from a juror to impeach
his verdict”). The vast majority of States adopted the no-
impeachment rule as a matter of common law. See, e.g.,
Bull v. Commonwealth, 

, 627–628 (1857) (“[T]he
practice appears to be now generally settled, to reject the
testimony of jurors when offered to impeach their verdict.
The cases on the subject are too numerous to be cited”);
Tucker v. Town Council of South Kingstown, 

. 558,
560 (1859) (collecting cases); State v. Coupenhaver, 

(1867) (“The law is well settled that a traverse juror
cannot be a witness to prove misbehavior in the jury in
                     Cite as: 580 U. S. ____ (2017)                   5

                        THOMAS, J., dissenting

regard to their verdict”); Peck v. Brewer, 

, 63
(1868) (“So far back as . . . 1823, the doctrine was held that
the affidavits of jurors cannot be heard to impeach their
verdict”); Heffron v. Gallupe, 

, 566 (1868) (rul-
ing inadmissible “depositions of . . . jurors as to what
transpired in the jury room”); Withers v. Fiscus, 

, 131–132 (1872) (“In the United States it seems to be
settled, notwithstanding a few adjudications to the con-
trary . . . , that such affidavits cannot be received”).2
   The Court today acknowledges that the States “adopted
the Mansfield rule as a matter of common law,” ante, at 6,
but ascribes no significance to that fact. I would hold that
it is dispositive. Our common-law history does not estab-
lish that—in either 1791 (when the Sixth Amendment was
ratified) or 1868 (when the Fourteenth Amendment was
ratified)—a defendant had the right to impeach a verdict
with juror testimony of juror misconduct. In fact, it
strongly suggests that such evidence was prohibited. In
the absence of a definitive common-law tradition permit-
ting impeachment by juror testimony, we have no basis to
invoke a constitutional provision that merely “follow[s] out
the established course of the common law in all trials for
crimes,” 3 Story §1785, at 662, to overturn Colorado’s
decision to preserve the no-impeachment rule, cf.
Boumediene v. Bush, 

, 832–833 (2008) (Scalia,
J., dissenting).
                       *    *     *
  Perhaps good reasons exist to curtail or abandon the no-
impeachment rule. Some States have done so, see Appen-
dix to majority opinion, ante, and others have not. Ulti-
——————
  2 Although two States declined to follow the rule in the mid-19th cen-

tury, see Wright v. Illinois & Miss. Tel. Co., 

, 210 (1866);
Perry v. Bailey, 

, 544–545 (1874), “most of the state courts”
had already “committed themselves upon the subject,” 8 Wigmore
§2354, at 702.
6             PENA-RODRIGUEZ v. COLORADO

                    THOMAS, J., dissenting

mately, that question is not for us to decide. It should be
left to the political process described by JUSTICE ALITO.
See post, at 5–7 (dissenting opinion). In its attempt to
stimulate a “thoughtful, rational dialogue” on race rela-
tions, ante, at 21, the Court today ends the political pro-
cess and imposes a uniform, national rule. The Constitu-
tion does not require such a rule. Neither should we.
   I respectfully dissent.
                 Cite as: 580 U. S. ____ (2017)            1

                     ALITO, J., dissenting

SUPREME COURT OF THE UNITED STATES
                         _________________

                          No. 15–606
                         _________________


MIGUEL ANGEL PENA-RODRIGUEZ, PETITIONER v.
               COLORADO
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF 

                      COLORADO

                        [March 6, 2017] 


   JUSTICE ALITO, with whom THE CHIEF JUSTICE and
JUSTICE THOMAS join, dissenting.
   Our legal system has many rules that restrict the ad­
mission of evidence of statements made under circum­
stances in which confidentiality is thought to be essential.
Statements made to an attorney in obtaining legal advice,
statements to a treating physician, and statements made
to a spouse or member of the clergy are familiar examples.
See Trammel v. United States, 

, 51 (1980).
Even if a criminal defendant whose constitutional rights
are at stake has a critical need to obtain and introduce
evidence of such statements, long-established rules stand
in the way. The goal of avoiding interference with confi­
dential communications of great value has long been
thought to justify the loss of important evidence and the
effect on our justice system that this loss entails.
   The present case concerns a rule like those just men­
tioned, namely, the age-old rule against attempting to
overturn or “impeach” a jury’s verdict by offering state­
ments made by jurors during the course of deliberations.
For centuries, it has been the judgment of experienced
judges, trial attorneys, scholars, and lawmakers that
allowing jurors to testify after a trial about what took
place in the jury room would undermine the system of
trial by jury that is integral to our legal system.
2                PENA-RODRIGUEZ v. COLORADO

                         ALITO, J., dissenting

   Juries occupy a unique place in our justice system. The
other participants in a trial—the presiding judge, the
attorneys, the witnesses—function in an arena governed
by strict rules of law. Their every word is recorded and
may be closely scrutinized for missteps.
   When jurors retire to deliberate, however, they enter a
space that is not regulated in the same way. Jurors are
ordinary people. They are expected to speak, debate,
argue, and make decisions the way ordinary people do in
their daily lives. Our Constitution places great value on
this way of thinking, speaking, and deciding. The jury
trial right protects parties in court cases from being
judged by a special class of trained professionals who do
not speak the language of ordinary people and may not
understand or appreciate the way ordinary people live
their lives. To protect that right, the door to the jury room
has been locked, and the confidentiality of jury delibera­
tions has been closely guarded.
   Today, with the admirable intention of providing justice
for one criminal defendant, the Court not only pries open
the door; it rules that respecting the privacy of the jury
room, as our legal system has done for centuries, violates
the Constitution. This is a startling development, and
although the Court tries to limit the degree of intrusion, it
is doubtful that there are principled grounds for prevent­
ing the expansion of today’s holding.
   The Court justifies its decision on the ground that the
nature of the confidential communication at issue in this
particular case—a clear expression of what the Court
terms racial bias1—is uniquely harmful to our criminal
——————
  1 The bias at issue in this case was a “bias against Mexican men.”

App. 160. This might be described as bias based on national origin or
ethnicity. Cf. Hernandez v. New York, 

, 355 (1991) (plu­
rality opinion); Hernandez v. Texas, 

, 479 (1954). How-
ever, no party has suggested that these distinctions make a substantive
                      Cite as: 580 U. S. ____ (2017)       3

                           ALITO, J., dissenting

justice system. And the Court is surely correct that even a
tincture of racial bias can inflict great damage on that
system, which is dependent on the public’s trust. But
until today, the argument that the Court now finds con­
vincing has not been thought to be sufficient to overcome
confidentiality rules like the one at issue here.
   Suppose that a prosecution witness gives devastating
but false testimony against a defendant, and suppose that
the witness’s motivation is racial bias. Suppose that the
witness admits this to his attorney, his spouse, and a
member of the clergy. Suppose that the defendant,
threatened with conviction for a serious crime and a
lengthy term of imprisonment, seeks to compel the attor­
ney, the spouse, or the member of the clergy to testify
about the witness’s admissions. Even though the constitu­
tional rights of the defendant hang in the balance, the
defendant’s efforts to obtain the testimony would fail. The
Court provides no good reason why the result in this case
should not be the same.
                             I
  Rules barring the admission of juror testimony to im­
peach a verdict (so-called “no-impeachment rules”) have a
long history. Indeed, they pre-date the ratification of the
Constitution. They are typically traced back to Vaise v.
Delaval, 1 T. R. 11, 99 Eng. Rep. 944 (K. B. 1785), in
which Lord Mansfield declined to consider an affidavit
from two jurors who claimed that the jury had reached its
verdict by lot. See Warger v. Shauers, 574 U. S. ___, ___
(2014) (slip op., at 4). Lord Mansfield’s approach “soon
took root in the United States,” ibid., and “[b]y the begin­
ning of [the 20th] century, if not earlier, the near-
universal and firmly established common-law rule in the
——————
difference in this case.
4              PENA-RODRIGUEZ v. COLORADO

                     ALITO, J., dissenting

United States flatly prohibited the admission of juror
testimony to impeach a jury verdict,” Tanner v. United
States, 

, 117 (1987); see 27 C. Wright & V.
Gold, Federal Practice and Procedure: Evidence §6071, p.
431 (2d ed. 2007) (Wright & Gold) (noting that the Mans­
field approach “came to be accepted in almost all states”).
   In McDonald v. Pless, 

(1915), this Court
adopted a strict no-impeachment rule for cases in federal
court. McDonald involved allegations that the jury had
entered a quotient verdict—that is, that it had calculated
a damages award by taking the average of the jurors’
suggestions. 

The Court held that evi­
dence of this misconduct could not be used. 

It
applied what it said was “unquestionably the general rule,
that the losing party cannot, in order to secure a new trial,
use the testimony of jurors to impeach their verdict.” 

that the defendant had a powerful
interest in demonstrating that the jury had “adopted an
arbitrary and unjust method in arriving at their verdict.”

“But,” the Court warned, “let it once be estab­
lished that verdicts . . . can be attacked and set aside on
the testimony of those who took part in their publication
and all verdicts could be, and many would be, followed by
an inquiry in the hope of discovering something which
might invalidate the finding.” 

to
“harass[ment]” of jurors and “the destruction of all frank­
ness and freedom of discussion and conference.” 

Ultimately, even though the no-impeachment
rule “may often exclude the only possible evidence of
misconduct,” relaxing the rule “would open the door to the
most pernicious arts and tampering with jurors.” 

(internal quotation marks omitted).
   The firm no-impeachment approach taken in McDonald
came to be known as “the federal rule.” This approach
categorically bars testimony about jury deliberations,
except where it is offered to demonstrate that the jury was
                     Cite as: 580 U. S. ____ (2017)                    5

                          ALITO, J., dissenting

subjected to an extraneous influence (for example, an
attempt to bribe a juror). 

, at ___ (slip op.,
at 5); Tanner, supra, at 117;2 see 27 Wright & Gold §6071,
at 432–433.
   Some jurisdictions, notably Iowa, adopted a more per­
missive rule. Under the Iowa rule, jurors were generally
permitted to testify about any subject except their “subjec­
tive intentions and thought processes in reaching a ver­
dict.” 

, at ___ (slip op., at 4). Accordingly,
the Iowa rule allowed jurors to “testify as to events or
conditions which might have improperly influenced the
verdict, even if these took place during deliberations within
the jury room.” 27 Wright & Gold §6071, at 432.
   Debate between proponents of the federal rule and the
Iowa rule emerged during the framing and adoption of
Federal Rule of Evidence 606(b). Both sides had their
supporters. The contending arguments were heard and
considered, and in the end the strict federal approach was
retained.
   An early draft of the Advisory Committee on the Federal
Rules of Evidence included a version of the Iowa rule, 51
F. R. D. 315, 387–388 (1971). That draft was forcefully
criticized, however,3 and the Committee ultimately pro­
——————
   2 As this Court has explained, the extraneous influence exception

“do[es] not detract from, but rather harmonize[s] with, the weighty
government interest in insulating the jury’s deliberative process.”

. The extraneous influence exception, like the
no-impeachment rule itself, is directed at protecting jury deliberations
against unwarranted interference. 

the Justice Department observed that “[s]trong policy

considerations continue to support” the federal approach and that
“[r]ecent experience has shown that the danger of harassment of jurors
by unsuccessful litigants warrants a rule which imposes strict limita­
tions on the instances in which jurors may be questioned about their
verdict.” Letter from R. Kliendienst, Deputy Attorney General, to
Judge A. Maris (Aug. 9, 1971), 117 Cong. Rec. 33648, 33655 (1971).
6                 PENA-RODRIGUEZ v. COLORADO

                          ALITO, J., dissenting

duced a revised draft that retained the well-established
federal approach. 

; see Committee
on Rules of Practice and Procedure of the Judicial Confer­
ence of the United States, Revised Draft of Proposed Rules
of Evidence for the United States Courts and Magistrates
73 (Oct. 1971). Expressly repudiating the Iowa rule, the
new draft provided that jurors generally could not testify
“as to any matter or statement occurring during the course
of the jury’s deliberations.” 

was
approved by the Judicial Conference and sent to this
Court, which adopted the rule and referred it to Congress.
56 F. R. D. 183, 265–266 (1972).
   Initially, the House rejected this Court’s version of Rule
606(b) and instead reverted to the earlier (and narrower)
Advisory Committee draft. 

; see
H. R. Rep. No. 93–650, pp. 9–10 (1973) (criticizing the
Supreme Court draft for preventing jurors from testifying
about “quotient verdict[s]” and other “irregularities which
occurred in the jury room”). In the Senate, however, the
Judiciary Committee favored this Court’s rule. The Com­
mittee Report observed that the House draft broke with
“long-accepted Federal law” by allowing verdicts to be
“challenge[d] on the basis of what happened during the
jury’s internal deliberations.” S. Rep. No. 93–1277, p. 13
(1974) (S. Rep.). In the view of the Senate Committee, the
House rule would have “permit[ted] the harassment of
former jurors” as well as “the possible exploitation of
disgruntled or otherwise badly-motivated ex-jurors.” 

Senator McClellan, an influential member of the Senate Judiciary
Committee, insisted that the “mischief in this Rule ought to be plain for
all to see” and that it would be impossible “to conduct trials, particu-
larly criminal prosecutions, as we know them today, if every verdict were
followed by a post-trial hearing into the conduct of the juror’s delibera­
tions.” Letter from Sen. J. McClellan to Judge A. Maris (Aug. 12,
1971), 

33645.
                 Cite as: 580 U. S. ____ (2017)           7

                     ALITO, J., dissenting

at 14. This result would have undermined the finality of
verdicts, violated “common fairness,” and prevented jurors
from “function[ing] effectively.” 

the House version of the rule and returned to the Court’s
rule. A Conference Committee adopted the Senate ver­
sion, see H. R. Conf. Rep. No. 93–1597, p. 8 (1974), and
this version was passed by both Houses and was signed
into law by the President.
   As this summary shows, the process that culminated in
the adoption of Federal Rule of Evidence 606(b) was the
epitome of reasoned democratic rulemaking. The “distin­
guished, Supreme Court-appointed” members of the Advi­
sory Committee went through a 7-year drafting process,
“produced two well-circulated drafts,” and “considered
numerous comments from persons involved in nearly
every area of court-related law.” Rothstein, The Proposed
Amendments to the Federal Rules of Evidence, 62 Geo.
L. J. 125 (1973). The work of the Committee was consid­
ered and approved by the experienced appellate and trial
judges serving on the Judicial Conference and by our
predecessors on this Court. After that, the matter went to
Congress, which “specifically understood, considered, and
rejected a version of [the rule] that would have allowed
jurors to testify on juror conduct during deliberations.”

. The judgment of all these par­
ticipants in the process, which was informed by their
assessment of an empirical issue, i.e., the effect that the
competing Iowa rule would have had on the jury system, is
entitled to great respect.
   Colorado considered this same question, made the same
judgment as the participants in the federal process, and
adopted a very similar rule. In doing so, it joined the
overwhelming majority of States. Ante, at 9. In the great
majority of jurisdictions, strong no-impeachment rules
continue to be “viewed as both promoting the finality of
verdicts and insulating the jury from outside influences.”
8              PENA-RODRIGUEZ v. COLORADO

                       ALITO, J., dissenting

Warger, 574 U. S., at ___ (slip op., at 4).
                                 II

                                 A

   Recognizing the importance of Rule 606(b), this Court
has twice rebuffed efforts to create a Sixth Amendment
exception—first in Tanner and then, just two Terms ago,
in Warger.
   The Tanner petitioners were convicted of committing
mail fraud and conspiring to defraud the United 

–110, 112–113. After the trial, two jurors
came forward with disturbing stories of juror misconduct.
One claimed that several jurors “consumed alcohol during
lunch breaks . . . causing them to sleep through the after­
noons.” 

The second added that jurors also
smoked marijuana and ingested cocaine during the trial.

This Court held that evidence of this
bacchanalia could properly be excluded under Rule 606(b).

   The Court noted that “[s]ubstantial policy considera­
tions support the common-law rule against the admission
of jury testimony to impeach a verdict.” 

While
there is “little doubt that postverdict investigation into
juror misconduct would in some instances lead to the
invalidation of verdicts reached after irresponsible or
improper juror behavior,” the Court observed, it is “not at
all clear . . . that the jury system could survive such efforts
to perfect it.” 

Allowing such post-verdict
inquiries would “seriously disrupt the finality of the pro­
cess.” 

undermine “full and frank dis­
cussion in the jury room, jurors’ willingness to return an
unpopular verdict, and the community’s trust in a system
that relies on the decisions of laypeople.” 

   The Tanner petitioners, of course, had a Sixth Amend­
ment right “to ‘a tribunal both impartial and mentally
competent to afford a hearing.’ ” 

(quoting Jor-
                 Cite as: 580 U. S. ____ (2017)            9

                     ALITO, J., dissenting

dan v. Massachusetts, 

, 176 (1912)). The
question, however, was whether they also had a right to
an evidentiary hearing featuring “one particular kind of
evidence inadmissible under the Federal 

–127. Turning to that question, the Court
noted again that “long-recognized and very substantial
concerns support the protection of jury deliberations from
intrusive inquiry.” 

By contrast, “[p]etitioners’
Sixth Amendment interests in an unimpaired jury . . .
[were] protected by several aspects of the trial process.”

four mechanisms that protect
defendants’ Sixth Amendment rights. First, jurors can be
“examined during voir dire.” 

trial the jury is observable by the court, by counsel, and by
court personnel.” 

observable by
each other, and may report inappropriate juror behavior to
the court before they render a verdict.” 

the trial a party may seek to impeach the verdict by
nonjuror evidence of misconduct.” 

of protection of petitioners’ right to a competent
jury” convinced the Court that the juror testimony was
properly excluded. 

negligence suit arising from a motor­
cycle crash. 574 U. S., at ___ (slip op., at 1). During voir
dire, the individual who eventually became the jury’s
foreperson said that she could decide the case fairly and
impartially. Id., at ___ (slip op., at 2). After the jury
returned a verdict in favor of the defendant, one of the
jurors came forward with evidence that called into ques­
tion the truthfulness of the foreperson’s responses during
voir dire. According to this juror, the foreperson revealed
during the deliberations that her daughter had once
caused a deadly car crash, and the foreperson expressed
the belief that a lawsuit would have ruined her daughter’s
life. 

COLORADO

                         ALITO, J., dissenting

   In seeking to use this testimony to overturn the jury’s
verdict, the plaintiff ’s primary contention was that Rule
606(b) does not apply to evidence concerning a juror’s
alleged misrepresentations during voir dire. If otherwise
interpreted, the plaintiff maintained, the rule would
threaten his right to trial by an impartial jury.4 The Court
disagreed, in part because “any claim that Rule 606(b) is
unconstitutional in circumstances such as these is fore­
closed by our decision in Tanner.” Id., at ___ (slip op., at
10). The Court explained that “[e]ven if jurors lie in voir
dire in a way that conceals bias, juror impartiality is
adequately assured by” two of the other Tanner safe­
guards: pre-verdict reports by the jurors and non-juror
evidence. 574 U. S., at ___ (slip op., at 10).
   Tanner and Warger fit neatly into this Court’s broader
jurisprudence concerning the constitutionality of evidence
rules. As the Court has explained, “state and federal
rulemakers have broad latitude under the Constitution to
establish rules excluding evidence from criminal trials.”
Holmes v. South Carolina, 

, 324 (2006) (in­
ternal quotation marks and alteration omitted). Thus,
evidence rules of this sort have been invalidated only if
they “serve no legitimate purpose or . . . are disproportion­
ate to the ends that they are asserted to promote.” 

Tanner and Warger recognized that Rule 606(b)
serves vital purposes and does not impose a disproportion­
ate burden on the jury trial right.
   Today, for the first time, the Court creates a constitu­
tional exception to no-impeachment rules. Specifically,
the Court holds that no-impeachment rules violate the
Sixth Amendment to the extent that they preclude courts
——————
  4 Although Warger was a civil case, we wrote that “[t]he Constitution

guarantees both criminal and civil litigants a right to an impartial
jury.” 574 U. S., at ___ (slip op., at 9).
                      Cite as: 580 U. S. ____ (2017)                    11

                          ALITO, J., dissenting

from considering evidence of a juror’s racially biased com­
ments. Ante, at 17. The Court attempts to distinguish
Tanner and Warger, but its efforts fail.
  Tanner and Warger rested on two basic propositions.
First, no-impeachment rules advance crucial interests.
Second, the right to trial by an impartial jury is adequately
protected by mechanisms other than the use of juror
testimony regarding jury deliberations. The first of these
propositions applies regardless of the nature of the juror
misconduct, and the Court does not argue otherwise.
Instead, it contends that, in cases involving racially biased
jurors, the Tanner safeguards are less effective and the
defendant’s Sixth Amendment interests are more pro­
found. Neither argument is persuasive.
                               B
   As noted above, Tanner identified four “aspects of the
trial process” that protect a defendant’s Sixth Amendment
rights: (1) voir dire; (2) observation by the court, counsel,
and court personnel; (3) pre-verdict reports by the jurors;
and (4) non-juror 

.5 Although
the Court insists that that these mechanisms “may be
compromised” in cases involving allegations of racial bias,
it addresses only two of them and fails to make a sus­
tained argument about either. Ante, at 16.
                                    1
  First, the Court contends that the effectiveness of voir
dire is questionable in cases involving racial bias because
——————
   5 The majority opinion in this case identifies a fifth mechanism: jury

instructions. It observes that, by explaining the jurors’ responsibilities,
appropriate jury instructions can promote “[p]robing and thoughtful
deliberation,” which in turn “improves the likelihood that other jurors
can confront the flawed nature of reasoning that is prompted or influ­
enced by improper biases.” Ante, at 20–21. This mechanism, like those
listed in Tanner, can help to prevent bias from infecting a verdict.
12                PENA-RODRIGUEZ v. COLORADO

                           ALITO, J., dissenting

pointed questioning about racial attitudes may highlight
racial issues and thereby exacerbate prejudice. 

from clear, however, that careful voir dire cannot
surmount this problem. Lawyers may use questionnaires
or individual questioning of prospective jurors6 in order to
elicit frank answers that a juror might be reluctant to
voice in the presence of other prospective jurors.7 More­
over, practice guides are replete with advice on conducting
effective voir dire on the subject of race. They outline a
variety of subtle and nuanced approaches that avoid
pointed questions.8 And of course, if an attorney is con­
——————
  6 Both   of those techniques were used in this case for other purposes.
App. 13–14; Tr. 56–78 (Feb. 23, 2010, morning session).
   7 See People v. Harlan, 

, 500 (Colo. 2000) (“The trial court

took precautions at the outset of the trial to foreclose the injection of
improper racial considerations by including questions concerning racial
issues in the jury questionnaire”); Brewer v. Marshall, 

,
996 (CA1 1997) (“The judge asked each juror, out of the presence of
other jurors, whether they had any bias or prejudice for or against
black persons or persons of Hispanic origin”); 6 W. LaFave, J. Israel, N.
King, & O. Kerr, Criminal Procedure §22.3(a), p. 92 (4th ed. 2015)
(noting that “[j]udges commonly allow jurors to approach the bench and
discuss sensitive matters there” and are also free to conduct “in cham­
bers discussions”).
   8 See, e.g., J. Gobert, E. Kreitzberg, & C. Rose, Jury Selection: The

Law, Art, and Science of Selecting a Jury §7:41, pp. 357–358 (3d ed.
2014) (explaining that “the issue should be approached more indirectly”
and suggesting the use of “[o]pen-ended questions” on subjects like “the
composition of the neighborhood in which the juror lives, the juror’s
relationship with co-workers or neighbors of different races, or the
juror’s past experiences with persons of other races”); W. Jordan, Jury
Selection §8.11, p. 237 (1980) (explaining that “the whole matter of
prejudice” should be approached “delicately and cautiously” and giving
an example of an indirect question that avoids the word “prejudice”); R.
Wenke, The Art of Selecting a Jury 67 (1979) (discussing questions that
could identify biased jurors when “your client is a member of a minority
group”); 

(suggesting that instead of “asking a juror if he is
‘prejudiced’ ” the attorney should “inquire about his ‘feeling,’ ‘belief’ or
‘opinion’ ”); 2 National Jury Project, Inc., Jurywork: Systematic Tech­
                     Cite as: 580 U. S. ____ (2017)                    13

                          ALITO, J., dissenting

cerned that a juror is concealing bias, a peremptory strike
may be used.9
  The suggestion that voir dire is ineffective in unearthing
bias runs counter to decisions of this Court holding that
voir dire on the subject of race is constitutionally required
in some cases, mandated as a matter of federal supervi-
sory authority in others, and typically advisable in any case

——————
niques §17.23 (E. Krauss ed., 2d ed. 2010) (listing sample questions
about racial prejudice); A. Grine & E. Coward, Raising Issues of Race in
North Carolina Criminal Cases, p. 8–14 (2014) (suggesting that attor­
neys “share a brief example about a judgment shaped by a racial
stereotype” to make it easier for jurors to share their own biased views),
http://defendermanuals.sog.unc.edu/race/8-addressing-race-trial (as last
visited Mar. 3, 2017); 

to 8–17 (suggesting additional strate­
gies and providing sample questions); T. Mauet, Trial Techniques 44
(8th ed. 2010) (suggesting that “likely beliefs and attitudes are more
accurately learned through indirection”); J. Lieberman & B. Sales,
Scientific Jury Selection 114–115 (2007) (discussing research suggest­
ing that “participants were more likely to admit they were unable to
abide by legal due process guarantees when asked open-ended ques­
tions that did not direct their responses”).
   9 To the extent race does become salient during voir dire, there is

social science research suggesting that this may actually combat rather
than reinforce the jurors’ biases. See, e.g., Lee, A New Approach to Voir
Dire on Racial Bias, 5 U. C. Irvine L. Rev. 843, 861 (2015) (“A wealth of
fairly recent empirical research has shown that when race is made
salient either through pretrial publicity, voir dire questioning of pro­
spective jurors, opening and closing arguments, or witness testimony,
White jurors are more likely to treat similarly situated Black and
White defendants the same way”). See also Sommers & Ellsworth,
White Juror Bias: An Investigation of Prejudice Against Black Defend­
ants in the American Courtroom, 7 Psychology, Pub. Pol’y, & L. 201,
222 (2001); Sommers & Ellsworth, How Much Do We Really Know
About Race and Juries? A Review of Social Science Theory and Re­
search, 78 Chi.-Kent L. Rev. 997, 1013–1014, 1027 (2003); Schuller,
Kazoleas, & Kawakami, The Impact of Prejudice Screening Procedures
on Racial Bias in the Courtroom, 33 Law & Human Behavior 320, 326
(2009); Cohn, Bucolo, Pride, & Somers, Reducing White Juror Bias: The
Role of Race Salience and Racial Attitudes, 39 J. Applied Soc. Psycho-
logy 1953, 1964–1965 (2009).
14                PENA-RODRIGUEZ v. COLORADO

                           ALITO, J., dissenting

if a defendant requests it. See Turner v. Murray, 

, 36–37 (1986); Rosales-Lopez v. United States, 

, 192 (1981) (plurality opinion); Ristaino v. Ross,

, 597, n. 9 (1976). If voir dire were not useful
in identifying racial prejudice, those decisions would be
pointless. Cf. 

(plurality opinion)
(noting “the ease with which [the] risk [of racial bias]
could have been minimized” through voir dire). Even the
majority recognizes the “advantages of careful voir dire” as
a “proces[s] designed to prevent racial bias in jury deliber­
ations.” Ante, at 20. And reported decisions substantiate
that voir dire can be effective in this regard. E.g., Brewer
v. Marshall, 

, 995–996 (CA1 1997); United
States v. Hasting, 

, 1271 (CA7 1984); People
v. Harlan, 

, 500 (Colo. 2000); see Brief for
Respondent 23–24, n. 7 (listing additional cases). Thus,
while voir dire is not a magic cure, there are good reasons
to think that it is a valuable tool.
   In any event, the critical point for present purposes is
that the effectiveness of voir dire is a debatable empirical
proposition. Its assessment should be addressed in the
process of developing federal and state evidence rules.
Federal and state rulemakers can try a variety of ap­
proaches, and they can make changes in response to the
insights provided by experience and research. The ap­
proach taken by today’s majority—imposing a federal
constitutional rule on the entire country—prevents exper­
imentation and makes change exceedingly hard.10
——————
  10 It is worth noting that, even if voir dire were entirely ineffective at

detecting racial bias (a proposition no one defends), that still would not
suffice to distinguish this case from Warger v. Shauers, 574 U. S. ___
(2014). After all, the allegation in Warger was that the foreperson had
entirely circumvented voir dire by lying in order to shield her bias. The
Court, nevertheless, concluded that even where “jurors lie in voir dire
in a way that conceals bias, juror impartiality is adequately assured”
                      Cite as: 580 U. S. ____ (2017)       15

                           ALITO, J., dissenting

                                2
  The majority also argues—even more cursorily—that
“racial bias may make it difficult for a juror to report
inappropriate statements during the course of juror delib­
erations.” Ante, at 16. This is so, we are told, because it is
difficult to “call [another juror] a bigot.” 

decision mandates the admission of
the testimony of one juror about a statement made by
another juror during deliberations, what the Court must
mean in making this argument is that jurors are less
willing to report biased comments by fellow jurors prior to
the beginning of deliberations (while they are still sitting
with the biased juror) than they are after the verdict is
announced and the jurors have gone home. But this is
also a questionable empirical assessment, and the Court’s
seat-of-the-pants judgment is no better than that of those
with the responsibility of drafting and adopting federal
and state evidence rules. There is no question that jurors
do report biased comments made by fellow jurors prior to
the beginning of deliberations. See, e.g., United States v.
McClinton, 

, 1184–1185 (CA7 1998); United
States v. Heller, 

, 1525–1529 (CA11 1986);
Tavares v. Holbrook, 

, 1–3 (CA1 1985) (Breyer,
J.); see Brief for Respondent 31–32, n. 10; Brief for United
States as Amicus Curiae 31. And the Court marshals no
evidence that such pre-deliberation reporting is rarer than
the post-verdict variety.
  Even if there is something to the distinction that the
Court makes between pre- and post-verdict reporting, it is
debatable whether the difference is significant enough to
merit different treatment. This is especially so because
post-verdict reporting is both more disruptive and may be
the result of extraneous influences. A juror who is ini-
—————— 

through other means. Id., at ___ (slip op., at 10).

16             PENA-RODRIGUEZ v. COLORADO

                      ALITO, J., dissenting

tially in the minority but is ultimately persuaded by other
jurors may have second thoughts after the verdict is an­
nounced and may be angry with others on the panel who
pressed for unanimity. In addition, if a verdict is unpopu­
lar with a particular juror’s family, friends, employer, co­
workers, or neighbors, the juror may regret his or her vote
and may feel pressured to rectify what the jury has done.
   In short, the Court provides no good reason to depart
from the calculus made in Tanner and Warger. Indeed,
the majority itself uses hedged language and appears to
recognize that this “pragmatic” argument is something of
a makeweight. Ante, at 16–17 (noting that the argument
is “not dispositive”); ante, at 16 (stating that the operation
of the safeguards “may be compromised, or they may prove
insufficient”).
                              III

                               A

  The real thrust of the majority opinion is that the Con­
stitution is less tolerant of racial bias than other forms of
juror misconduct, but it is hard to square this argument
with the nature of the Sixth Amendment right on which
petitioner’s argument and the Court’s holding are based.
What the Sixth Amendment protects is the right to an
“impartial jury.” Nothing in the text or history of the
Amendment or in the inherent nature of the jury trial
right suggests that the extent of the protection provided
by the Amendment depends on the nature of a jury’s
partiality or bias. As the Colorado Supreme Court aptly
put it, it is hard to “discern a dividing line between differ­
ent types of juror bias or misconduct, whereby one form of
partiality would implicate a party’s Sixth Amendment
right while another would not.” 

, 293
                     Cite as: 580 U. S. ____ (2017)                  17

                         ALITO, J., dissenting

(2015).11
   Nor has the Court found any decision of this Court
suggesting that the Sixth Amendment recognizes some
sort of hierarchy of partiality or bias. The Court points to
a line of cases holding that, in some narrow circumstances,
the Constitution requires trial courts to conduct voir dire
on the subject of race. Those decisions, however, were not
based on a ranking of types of partiality but on the Court’s
conclusion that in certain cases racial bias was especially
likely. See 

, n. 12 (plurality opin­
ion) (requiring voir dire on the subject of race where there
is “a particularly compelling need to inquire into racial
prejudice” because of a qualitatively higher “risk of racial
bias”); 

(explaining that the
requirement applies only if there is a “constitutionally
significant likelihood that, absent questioning about
racial prejudice, the jurors would not be [impartial]”).12
Thus, this line of cases does not advance the majority’s
argument.
   It is undoubtedly true that “racial bias implicates
unique historical, constitutional, and institutional con­
cerns.” Ante, at 16. But it is hard to see what that has to
do with the scope of an individual criminal defendant’s
Sixth Amendment right to be judged impartially. The
Court’s efforts to reconcile its decision with McDonald,
——————
  11 The majority’s reliance on footnote 3 of Warger, ante, at 12–13, is
unavailing. In that footnote, the Court noted that some “cases of juror
bias” might be “so extreme” as to prompt the Court to “consider whether
the usual safeguards are or are not sufficient to protect the integrity
of the process.” 574 U. S., at ___–___, n. 3 (slip op., at 10–11, n. 3)
(emphasis added). Considering this question is very different from
adopting a constitutionally based exception to long-established no-
impeachment rules.
  12 In addition, those cases did not involve a challenge to a long-

established evidence rule. As such, they offer little guidance in per­
forming the analysis required by this case.
18                PENA-RODRIGUEZ v. COLORADO

                          ALITO, J., dissenting

Tanner, and Warger illustrate the problem. The Court
writes that the misconduct in those cases, while “troubling
and unacceptable,” was “anomalous.” Ante, at 15. By
contrast, racial bias, the Court says, is a “familiar and
recurring evil” that causes “systemic injury to the admin­
istration of justice.” Ante, at 15–16.
   Imagine two cellmates serving lengthy prison terms.
Both were convicted for homicides committed in unrelated
barroom fights. At the trial of the first prisoner, a juror,
during deliberations, expressed animosity toward the
defendant because of his race. At the trial of the second
prisoner, a juror, during deliberations, expressed animos­
ity toward the defendant because he was wearing the
jersey of a hated football team. In both cases, jurors come
forward after the trial and reveal what the biased juror
said in the jury room. The Court would say to the first
prisoner: “You are entitled to introduce the jurors’ testi­
mony, because racial bias is damaging to our society.” To
the second, the Court would say: “Even if you did not have
an impartial jury, you must stay in prison because sports
rivalries are not a major societal issue.”
   This disparate treatment is unsupportable under the
Sixth Amendment. If the Sixth Amendment requires the
admission of juror testimony about statements or conduct
during deliberations that show one type of juror partiality,
then statements or conduct showing any type of partiality
should be treated the same way.
                             B
  Recasting this as an equal protection case would not
provide a ground for limiting the holding to cases involv­
ing racial bias. At a minimum, cases involving bias based
on any suspect classification—such as national origin13 or
——————
 13 See   Cleburne v. Cleburne Living Center, Inc., 

, 440
                    Cite as: 580 U. S. ____ (2017)                 19

                         ALITO, J., dissenting

religion14—would merit equal treatment. So, I think,
would bias based on sex, United States v. Virginia, 

, 531 (1996), or the exercise of the First Amend­
ment right to freedom of expression or association. See
Regan v. Taxation With Representation of Washington, 

, 545 (1983). Indeed, convicting a defendant on
the basis of any irrational classification would violate the
Equal Protection Clause.
   Attempting to limit the damage worked by its decision,
the Court says that only “clear” expressions of bias must
be admitted, ante, at 17, but judging whether a statement
is sufficiently “clear” will often not be easy. Suppose that
the allegedly biased juror in this case never made refer­
ence to Peña-Rodriguez’s race or national origin but said
that he had a lot of experience with “this macho type” and
knew that men of this kind felt that they could get their
way with women. Suppose that other jurors testified that
they were certain that “this macho type” was meant to
refer to Mexican or Hispanic men. Many other similarly
suggestive statements can easily be imagined, and under
today’s decision it will be difficult for judges to discern the
dividing line between those that are “clear[ly]” based on
racial or ethnic bias and those that are at least somewhat
ambiguous.
                            IV
  Today’s decision—especially if it is expanded in the
ways that seem likely—will invite the harms that no-
impeachment rules were designed to prevent.
  First, as the Court explained in Tanner, “postverdict
scrutiny of juror conduct” will inhibit “full and frank dis­
——————
(1985).
  14 See, e.g., United States v. Armstrong, 

, 464 (1996);

Burlington Northern R. Co. v. Ford, 

, 651 (1992); New
Orleans v. Dukes, 

, 303 (1976) (per curiam).
20               PENA-RODRIGUEZ v. COLORADO

                         ALITO, J., dissenting

cussion in the jury 

–121; see also

–268 (warning that the use of
juror testimony about misconduct during deliberations
would “make what was intended to be a private delibera­
tion, the constant subject of public investigation—to the
destruction of all frankness and freedom of discussion and
conference”). Or, as the Senate Report put it: “[C]ommon
fairness requires that absolute privacy be preserved for
jurors to engage in the full and free debate necessary to
the attainment of just verdicts. Jurors will not be able to
function effectively if their deliberations are to be scruti­
nized in post-trial litigation.” S. Rep., at 14.
   Today’s ruling will also prompt losing parties and their
friends, supporters, and attorneys to contact and seek to
question jurors, and this pestering may erode citizens’
willingness to serve on juries. Many jurisdictions now
have rules that prohibit or restrict post-verdict contact
with jurors, but whether those rules will survive today’s
decision is an open question—as is the effect of this deci­
sion on privilege rules such as those noted at the outset of
this opinion.15
   Where post-verdict approaches are permitted or occur,

——————
  15 The majority’s emphasis on the unique harms of racial bias will not

succeed at cabining the novel exception to no-impeachment rules, but it
may succeed at putting other kinds of rules under threat. For example,
the majority approvingly refers to the widespread rules limiting attor­
neys’ contact with jurors. Ante, at 17–18. But under the reasoning of
the majority opinion, it is not clear why such rules should be enforced
when they come into conflict with a defendant’s attempt to introduce
evidence of racial bias. For instance, what will happen when a lawyer
obtains clear evidence of racist statements by contacting jurors in
violation of a local rule? (Something similar happened in 

.) It remains to be seen whether rules of this type—or
other rules which exclude probative evidence, such as evidentiary
privileges—will be allowed to stand in the way of the “imperative to
purge racial prejudice from the administration of justice.” Ante, at 13.
                  Cite as: 580 U. S. ____ (2017)            21

                      ALITO, J., dissenting

there is almost certain to be an increase in harassment,
arm-twisting, and outright coercion.         See 

; S. Rep., at 14 (explaining that a laxer rule
“would permit the harassment of former jurors by losing
parties as well as the possible exploitation of disgruntled
or otherwise badly-motivated 

. As one treatise explains, “[a] juror who reluctantly
joined a verdict is likely to be sympathetic to overtures by
the loser, and persuadable to the view that his own con­
sent rested on false or impermissible considerations, and
the truth will be hard to know.” 3 C. Mueller & L. Kirk­
patrick, Federal Evidence §6:16, p. 75 (4th ed. 2013).
   The majority’s approach will also undermine the finality
of verdicts. “Public policy requires a finality to litigation.”
S. Rep., at 14. And accusations of juror bias—which may
be “raised for the first time days, weeks, or months after
the verdict”—can “seriously disrupt the finality of the
process.” 

. This threatens to
“degrad[e] the prominence of the trial itself ” and to send
the message that juror misconduct need not be dealt with
promptly. Engle v. Isaac, 

, 127 (1982). See
H. R. Conf. Rep. No. 93–1597, at 8 (“The Conferees believe
that jurors should be encouraged to be conscientious in
promptly reporting to the court misconduct that occurs
during jury deliberations”).
   The Court itself acknowledges that strict no-
impeachment rules “promot[e] full and vigorous discus­
sion,” protect jurors from “be[ing] harassed or annoyed by
litigants seeking to challenge the verdict,” and “giv[e]
stability and finality to verdicts.” Ante, at 9. By the ma­
jority’s own logic, then, imposing exceptions on no-
impeachment rules will tend to defeat full and vigorous
discussion, expose jurors to harassment, and deprive
verdicts of stability.
   The Court’s only response is that some jurisdictions
already make an exception for racial bias, and the Court
22             PENA-RODRIGUEZ v. COLORADO

                      ALITO, J., dissenting

detects no signs of “a loss of juror willingness to engage in
searching and candid deliberations.” Ante, at 19. One
wonders what sort of outward signs the Court would
expect to see if jurors in these jurisdictions do not speak as
freely in the jury room as their counterparts in jurisdic­
tions with strict no-impeachment rules. Gathering and
assessing evidence regarding the quality of jury delibera­
tions in different jurisdictions would be a daunting enter­
prise, and the Court offers no indication that anybody has
undertaken that task.
   In short, the majority barely bothers to engage with the
policy issues implicated by no-impeachment rules. But
even if it had carefully grappled with those issues, it still
would have no basis for exalting its own judgment over
that of the many expert policymakers who have endorsed
broad no-impeachment rules.
                             V
  The Court’s decision is well-intentioned. It seeks to
remedy a flaw in the jury trial system, but as this Court
said some years ago, it is questionable whether our system
of trial by jury can endure this attempt to perfect it.

.
  I respectfully dissent.