In the

    United States Court of Appeals
                 For the Seventh Circuit
No. 18-1343

UNITED STATES OF AMERICA,
                                                   Plaintiff-Appellee,

                                 v.


BLAIR COOK,
                                               Defendant-Appellant.


        Appeal from the United States District Court for the
                    Western District of Wisconsin.
       No. 3:17-cr-00048-001 — James D. Peterson, Chief Judge.



  ARGUED SEPTEMBER 13, 2018 — DECIDED JANUARY 28, 2019


   Before FLAUM, MANION, and ROVNER, Circuit Judges.
   ROVNER, Circuit Judge. A jury convicted Blair Cook of being
an unlawful user of a controlled substance (marijuana) in
possession of a firearm. See 18 U.S.C. § 922(g)(3). Cook appeals
his conviction, contending that the statute underlying his
conviction is facially vague, that it improperly limits his
Second Amendment right to possess a firearm, and that the
2                                                       No. 18-1343

district court did not properly instruct the jury as to who
constitutes an unlawful user of a controlled substance. We
affirm Cook’s conviction.
                                  I.
    On May 25, 2017, officers of the Madison, Wisconsin police
department conducted a traffic stop of the car that Cook was
driving. When officers approached the car and spoke with
Cook, they noticed a strong odor of marijuana emanating from
the car. Apart from the possibility that Cook was driving under
the influence of marijuana, Cook was also driving on a
suspended license and without a license plate on the front of
his vehicle, so the officers decided to detain him and ordered
him to step out of the vehicle. Officer Matthew Wentzel
removed a loaded, .40-caliber Glock Model 23 pistol from a
holster under Cook’s shoulder. The gun had an extended 22-
round capacity magazine with 19 bullets remaining. Cook was
transported to the police station for further questioning.
During a recorded interview at the station, Cook acknowl-
edged to Wentzel that he had used marijuana almost daily for
nearly ten years (since the age of 14), that he did so because
marijuana calmed him down, and that he had smoked two
“blunts” earlier that day.1 On prodding from the police, Cook
ultimately produced a small packet from his groin area
containing a half ounce of marijuana.
   Cook had purchased the firearm from Max Creek Outdoors
in Oregon, Wisconsin on April 2, 2017. At the time of the


1
  “Blunt” is a street term for a cigar from which the tobacco has been
removed and replaced with marijuana.
No. 18-1343                                                   3

purchase, he was required to complete a Firearms Transaction
Record Form 4473 promulgated by the Bureau of Alcohol,
Tobacco, Firearms, and Explosives (“ATF”). On that form,
Cook answered “No” to the question, “Are you an unlawful
user of, or addicted to, marijuana or any depressant, stimulant,
narcotic drug, or any other controlled substance?” Directly
under that question the reader of the form was admonished,
“Warning: The use or possession of marijuana remains
unlawful under Federal law regardless of whether it has been
legalized or decriminalized for medical or recreational pur-
poses in the state where you reside.”
    A grand jury subsequently charged Cook with two of-
fenses: possession of a firearm and ammunition by an “unlaw-
ful user” of marijuana, in violation of section 922(g)(3), and
making a false statement (that he was not an unlawful user of
marijuana) on the ATF form in connection with his purchase of
a firearm and ammunition, in violation of 18 U.S.C.
§ 924(a)(1)(A).
    Cook moved to dismiss both counts of the indictment on
the ground that the term “unlawful user” of a controlled
substance found in sections 922(g)(3) and 924(a)(1)(A) is
unconstitutionally vague. The district court denied the motion.
R. 21 at 2–3.
    The district court subsequently gave the following instruc-
tion to the jury as to who constitutes an “unlawful user” of
marijuana:
       The defendant was an unlawful user of mari-
       juana if he used marijuana on a regular and
       ongoing basis for a period of time that began
4                                                     No. 18-1343

       before and continued through the date of the
       charged offense. The government is not required
       to prove that the defendant was under the
       influence of marijuana when he filled out the
       Firearms Transaction Record or when he pos-
       sessed the firearm. The government is not re-
       quired to prove that the defendant used mari-
       juana on any particular day, or within a certain
       number of days of when he committed the
       charged offenses.
R. 44 at 8; R. 56 at 70–71 (emphasis in original). The defense
rejected the government’s offer to include an additional
sentence in this instruction advising the jury that a one-time
use of marijuana is insufficient to render the defendant an
“unlawful user” within the meaning of either statute. R. 87 at
17.
   Following a one-day trial, a jury convicted Cook on the
section 922(g)(3) charge but was unable to reach a verdict on
the section 924 charge, which the district court dismissed
without prejudice, R. 53. The district court denied Cook’s Rule
33 motions for a new trial (R. 73) and ordered Cook to serve a
four-year term of probation in lieu of any term of imprison-
ment (R. 76).
                                II.
    Section 922(g)(3) provides in relevant part that “[i]t shall be
unlawful for any person … who is an unlawful user of or
addicted to any controlled substance (as defined in section 102
of the Controlled Substances Act (21 U.S.C. § 802)) … to …
possess in or affecting commerce, any firearm or ammunition
No. 18-1343                                                        5

… .” Marijuana is a Schedule I controlled substance, see 21
U.S.C. § 812(c)(10), and because the Glock pistol Cook pur-
chased had previously traveled in interstate commerce (it was
manufactured in Smyrna, Georgia), section 922(g)(3) forbade
Cook’s possession of the gun at the time of the May 2017 traffic
stop provided he qualified as an “unlawful user” of marijuana,
which the jury necessarily found that he did.
    Cook challenges his conviction pursuant to this statute on
three grounds: (1) the statute is facially vague as to who
constitutes an “unlawful user” of a controlled substance; (2)
the statute violates his Second Amendment right to possess a
firearm; and (3) the jury instruction defining “unlawful user”
was inadequate. For the reasons that follow, we find none of
these arguments to be persuasive.
A. Facial vagueness challenge to section 922(g)(3).
    Cook contends that section 922(g)(3) is vague on its face,
such that his conviction violates the Fifth Amendment’s due
process clause. The void-for-vagueness doctrine requires that
a criminal statute define an offense with sufficient clarity that
an ordinary person has fair notice of what conduct is prohib-
ited and so as to avoid arbitrary and discriminatory enforce-
ment. See, e.g., Skilling v. United States, 

, 402–03, 

, 2927–28 (2010); United States v. Sylla, 

,
774–75 (7th Cir. 2015). “What renders a statute vague is not the
possibility that it will sometimes be difficult to determine
whether the incriminating fact it establishes has been proved;
but rather the indeterminacy of precisely what that fact is.”
United States v. Williams, 

, 306, 

, 1846
(2008).
6                                                             No. 18-1343

    The general practice, outside of the First Amendment
context,2 has been to consider the purported vagueness of a
statute in light of the facts of the particular case—i.e., as
applied—rather than in the abstract. See, e.g., Maynard v.
Cartwright, 

, 361, 

, 1857–58 (1988);
United States v. Johnson, 

, 370 (7th Cir. 2017). This
means, of course, that a litigant challenging the statute ordi-
narily must show that it is vague as applied to him; and if the
statute undoubtedly applies to his conduct, he will not be
heard to argue that the statute is vague as to one or more
hypothetical scenarios. See Holder v. Humanitarian Law Project,

, 18–19, 

, 2718–19 (2010) (quoting
Village of Hoffman Estates v. Flipside Hoffman Estates, Inc., 

, 495, 

, 1191 (1982)); Broadrick v. Okla-
homa, supra 

, 93 S. Ct. at 2915 (collecting
cases).
   Nonetheless, the Supreme Court has on a number of
occasions entertained facial challenges to criminal statutes that
do not implicate First Amendment concerns. See, e.g., 

–14, 130 S. Ct. at 2927–33 (honest services fraud);
City of Chicago v. Morales, 

, 52–64, 

,
1857–63 (1999) (loitering by gang members in public spaces);
Lanzetta v. New Jersey, 

, 453–58, 

, 619–21
(1939) (gang participation); United States v. L. Cohen Grocery Co.,

, 89–93, 

, 300–01 (1921) (price gouging).
As we noted in United States v. Jones, 

(7th Cir.


2
  When a statute implicates activities protected by the First Amendment,
there is a special concern that free speech and expression not be chilled. See
Broadrick v. Oklahoma, 

, 611–12, 

, 2915–16 (1973).
No. 18-1343                                                        7

2012), abrogated on other grounds by Johnson v. United States, 

(2015), the common thread uniting these cases with
facial challenges in the First Amendment context appears to be
a concern (or at least a colorable contention) that the chal-
lenged statute “simply has no core” and lacks “any ascertain-
able standard for inclusion and exclusion, ”id. at 703 (quoting
Smith v. Goguen, 

, 578, 

, 1249 (1974)).
Such a standardless statute poses a trap for the person acting
in good faith, who is given no guidepost by which he can
divine what sort of conduct is prohibited. See Colautti v.
Franklin, 

, 395, 

, 685 (1979), overruled in
part on other grounds, Webster v. Reproductive Health Servs., 

, 

(1989). The concern is heightened
when the statute contains no mens rea requirement, 

, 99 S. Ct. at 685–86, and the uncertainty as to
exactly what is proscribed “threatens to inhibit the exercise of
constitutionally protected rights,” 

99 S. Ct. at 683. See
also 

, 119 S. Ct. at 1858.
    The statutory prohibition at issue here does not present
such concerns. True enough, section 922(g)(3) does implicate
Cook’s Second Amendment right to possess a gun. But the
prohibition is not a strict liability offense requiring no mens rea,
as in Colautti. By virtue of the separate penalties provision
found in 18 U.S.C. § 924(a)(2), a violation of section 922(g)(3)
must be knowing – that is, the defendant must have knowl-
edge of the facts that constitute the offense. See 

, 130 S. Ct. at 2720 (“the knowledge requirement of the
statute further reduces any potential for vagueness, as we have
held with respect to other statutes containing a similar require-
ment”) (collecting cases); United States v. Johnson, 

,
8                                                     No. 18-1343

853 (7th Cir. 2018) (word “knowingly” cures any potential
vagueness in challenged condition of supervised release)
(citing Screws v. United States, 

, 102, 

,
1036 (1945)). More importantly, there is, as our decision in
United States v. Yancey, 

(7th Cir. 2010) (per curiam)
makes clear, a readily appreciable core of conduct prohibited
by the statute.
    Yancey construes the term “unlawful user,” as used in
section 922(g)(3), to mean one who regularly or habitually
ingests controlled substances in a manner other than as
prescribed by a physician. 

Our opinion adds that
such use must be contemporaneous with the defendant’s
possession of a gun. 

(collecting cases); see also United
States v. Grap, 

, 446 (7th Cir. 2005) (adopting same
contemporaneity requirement for purposes of U.S.S.G.
§ 2K2.1(a)(6), which specifies the base offense level for
“prohibited person” convicted of firearms offense) (collecting
cases). We rendered this interpretation of section 922(g)(3) in
the course of rejecting a Second Amendment challenge to the
statute. Noting the well-established link between chronic drug
use and violence, we concluded that section 922(g)(3)’s ban on
gun possession by those who regularly engage in illegal drug
use was substantially related to the important government
interest in preventing violent 

–87. We
must take into account Yancey’s gloss on the statute in evaluat-
ing Cook’s vagueness claim. See 

, 130
S. Ct. at 2929 (“It has long been our practice, … before striking
a federal statute as vague, to consider whether the prescription
is amenable to a limiting construction.”); Pleasureland Museum,
No. 18-1343                                                      9

Inc. v. Beutter, 

, 995–96 (7th Cir. 2002); Waldron v.
McAtee, 

, 1354 (7th Cir. 1983).
    Cook is thus not in a position to claim that the statute is so
indefinite as to inhibit the legitimate exercise of Second
Amendment rights. Whatever doubt there might be at the
margins as to conduct potentially reached by section 922(g)(3),
there can be no doubt as to the core of conduct that the statute
(as construed by Yancey) proscribes: the possession of a firearm
by an individual engaged in the regular, non-prescribed use of
a controlled substance. Indeed, it would appear that Cook’s
conduct—possession of a firearm in the midst of a nearly ten-
year period of daily marijuana use—epitomizes that core,
which may explain why Cook is so keen to challenge the
statute on its face rather than as applied.
     Cook nonetheless suggests that the Supreme Court’s recent
decision in Johnson authorizes his facial vagueness challenge,
regardless of whether the statute is vague as applied to his
particular conduct. Johnson declared the (now defunct) residual
clause of the Armed Career Criminal Act (“ACCA”) to be
impermissibly vague without requiring the defendant to first
show that the clause was vague as applied to 

. The ACCA specifies an enhanced sentence of 15 years to
life for one convicted of a firearms offense if the defendant has
three or more prior convictions for either a “serious drug
offense” or a “violent felony.” 18 U.S.C. § 924(e)(1). As relevant
here, the statute defines “violent felony” to mean a crime
punishable by a year or more in prison which “is burglary,
arson, or extortion, involves use of explosives, or otherwise
involves conduct that presents a serious potential risk of physical
injury to another[.]” § 924(e)(2)(B)(ii) (emphasis ours). The Court
10                                                    No. 18-1343

previously had construed section 924(e)(2)(B)(ii) generally to
require a sentencing court to employ a categorical approach
focusing on the generic version of an offense (that is, what the
elements of the offense required), rather than the defendant’s
actual conduct, in deciding whether his prior conviction
qualified as a violent felony. See Taylor v. United States, 

, 602, 

, 2160 (1990). In view of the categorical
inquiry mandated by Taylor, two aspects of the residual clause
we have italicized led the Supreme Court in Johnson to con-
clude that this clause was impermissibly vague: (1) after
postulating the archetypal version of the crime, one had to
decide how much risk of physical injury was posed by that
idealized version of the offense; and (2) one also had to
consider how much risk of injury was required to render an
offense violent as compared with the offenses expressly
identified in the statute (burglary, arson, extortion, and
offenses involving the use of 

–58.
Both inquiries were plagued by uncertainty, as evidenced by
both the Court’s own demonstrated inability in a series of prior
residual clause cases to articulate a “principled and objective
standard” for identifying crimes that present a serious risk of
physical injury, 

as well as the “numerous splits
among the lower federal courts,” where the clause had proved
“nearly impossible to apply consistently,” 

(quoting
Chambers v. United States, 

, 133, 

, 694
(2009) (Alito, J., concurring in judgment)). “Nine years’
experience trying to derive meaning from the residual clause
convinces us that we have embarked upon a failed enterprise,”
the Court concluded. “Each of the uncertainties in the residual
clause may be tolerable in isolation, but ‘their sum makes a
No. 18-1343                                                    11

task for us which at best could be only guesswork.’” 

States v. Evans, 

, 495, 

,
641 (1948)).
    In declaring the residual clause to violate the due process
clause, the Court expressly rejected the government’s conten-
tion that an otherwise vague statute is constitutional so long as
“there is some conduct that clearly falls within the provision’s
grasp.” 

While acknowledging that statements in
some of its opinions could be read to support such a rule, the
Court emphasized that its prior holdings squarely contradicted
such a practice. 

Simply because it is possible to
envision some factual scenarios that would violate an
ambiguously-worded statute is not enough to rescue that
statute from a vagueness challenge, the Court made clear. 

    The Court was also at pains to emphasize, however, that
simply because a criminal statute uses qualitative language to
articulate a liability standard does not mean that the statute is
impermissibly vague, especially when the statute under
scrutiny calls upon the court to apply that standard to a
concrete set of facts. 

see also 

       As a general matter, we do not doubt the consti-
       tutionality of laws that call for the application of
       a qualitative standard such as “substantial risk”
       to real-world conduct; “the law is full of in-
       stances where a man’s fate depends on his
       estimating rightly … some matter of degree,”
       Nash v. United States, 

, 377, 

(1913). The residual clause, however, re-
12                                                                No. 18-1343

         quires application of the “serious potential risk”
         standard to an idealized ordinary case of the
         crime. Because “the elements necessary to
         determine the imaginary ideal are uncertain
         both in nature and degree of effect,” this abstract
         inquiry offers significantly less predictability
         than one “[t]hat deals with the actual, not with
         an imaginary condition other than the facts.”
         International Harvester Co. of America v. Kentucky,
         

, 223, 

.
    It is not clear how much Johnson—and the Court’s follow-on
decision last term in Sessions v. Dimaya, 

(2018),
which invalidated similar language in the Immigration and
Nationality Act—actually expand the universe of litigants who
may mount a facial challenge to a statute they believe is vague.
Not surprisingly, Cook contends that Johnson permits any
defendant who can postulate doubts as to what particular
conduct a criminal statute does or does not reach to pursue a
facial challenge to that statute, without having to show that
there is any real question as to whether his own conduct is
proscribed. It is true that Johnson puts to rest the notion—found
in any number of pre-Johnson cases3—that a litigant must show


3
  See, e.g., United States v. Salerno, 

, 745, 

, 2100
(1987) (“A facial challenge to a legislative Act is, of course, the most difficult
challenge to mount successfully, since the challenger must establish that no
set of circumstances exists under which the Act would be valid.”); 

, 2581 (Alito, J., dissenting); Hegwood v. City of Eau Claire,
                                                                    (continued...)
No. 18-1343                                                                 13

that the statute in question is vague in all of its applications in
order to successfully mount a facial 

. And, as we have mentioned, Johnson likewise rejects the
notion that simply because one can point to some conduct that
the statute undoubtedly would reach is alone sufficient to save
it from a vagueness challenge. 

has those aspects of
Johnson going for him. But so much of the Court’s analysis in
Johnson deals with a statute that is in key respects sui generis. In
particular, it was the categorical approach called for by the
ACCA’s residual clause—requiring courts to look not at the
actual conduct underlying the defendant’s prior conviction but
rather at the archetypal version of the offense and then to
consider whether the risk of injury posed by that version was
sufficient to render the crime violent—which the court found
to be particularly vexing. 

Assessing the degree
of risk posed by an idealized “typical” version of an offense
was significantly different, as the Court emphasized, from
looking at the risks posed by a set of actual, concrete facts. 

see also 

–16.
    Cook’s appeal, by contrast, presents a much more routine
vagueness challenge that highlights some imprecision in the
statutory language and posits uncertainty as to whether the
statute might apply to certain hypothetical facts. But section
922(g)(3) does not call for the court to engage in any abstract
analysis; it calls on the court to apply the statutory prohibition


3
  (...continued)

, 604 (7th Cir. 2012); Sherman ex rel. Sherman v. Koch, 

, 520 (7th Cir. 2010); Schor v. City of Chicago, 

, 781 (7th Cir.
2009).
14                                                                 No. 18-1343

to a defendant’s real-world conduct. See United States v.
Douglas, 

, 11, 14 (1st Cir. 2018), pet’n for cert. filed, No.
18-7331 (U.S. Jan. 7, 2019); Ovalles v. United States, 

, 1233–34, 1252 (11th Cir. 2018) (en banc); United States v.
Barrett, 

, 178–79, 182 (2d Cir. 2018), pet’n for cert.
filed, No. 18-6985 (U.S. Dec. 3, 2018); United States v. Larson,
— F. App’x —, 

, at *2 (4th Cir. Sept. 4, 2018)
(per curiam) (unpublished). Moreover, there is, as we have
discussed, a readily appreciable core of conduct that the statute
reaches: If one regularly uses marijuana or another controlled
substance other than as directed by a physician, he may not
possess a firearm so long as the use persists. Consequently,
citizens who wish to exercise their Second Amendment rights
and law enforcement officials alike have reasonable notice of
what is prohibited. This is not a “hopelessly indeterminate”
statute that leaves everyone to guess what conduct is legal and
what conduct is proscribed.4 The statute, as construed by


4
   We recognize that a liability standard turning on the regularity of a
particular activity can in some instances present a vagueness problem. See
Whatley v. Zatecky, 

(7th Cir. 2016) (finding impermissibly vague
statute specifying enhanced sentence for individual possessing controlled
substance within 1000 feet of “youth program center,” defined as any
building that provides youth-oriented programs or services “ on a regular
basis”). In contrast to Whatley, the statute at issue here is not a strict-liability
provision, and one’s liability under section 922(g)(3) turns on the regularity
of one’s own conduct rather than the activity occurring in a building that
may exhibit no indicia of what programs and services are provided therein
and how often. One who uses a controlled substance necessarily knows
how often he does so. And whatever doubt there might be as to when one’s
drug use becomes regular, Cook as a daily user of marijuana over the
                                                                    (continued...)
No. 18-1343                                                                 15

Yancey, does incorporate a qualitative liability standard, and
one can posit, as Cook does, hypothetical scenarios which
present close questions as to whether an individual’s use of a
controlled substance is unlawful, whether it qualifies as
regular and ongoing, and/or whether that use is sufficiently
contemporaneous with his or her possession of a firearm. But
in contrast with the residual clause, there is no judicial history
of courts struggling to appreciate what particular conduct
Congress meant to reach with section 922(g)(3) or to apply the
statutory terms to varying sets of facts. The uniform rejection
of as-applied vagueness challenges to section 922(g)(3) by itself
suggests that it is not anything like the sort of problematic
statute the Court confronted in Johnson. See United States v.
Bramer, 

, 909–10 (8th Cir. 2016) (per curiam); United
States v. Edwards, 

, 1162 (10th Cir. 2008); United
States v. Patterson, 

, 836 (5th Cir. 2005); United States
v. Purdy, supra 

. And simply because it may
sometimes be difficult to determine if an individual’s drug use
meets section 922(g)(3)’s standard for liability does not signify
that the statute is impermissibly vague, given that there is no
doubt as to the essence of what the statute forbids: the posses-
sion of a firearm by one who is engaged in the regular and
ongoing use of a controlled substance other than as prescribed



4
  (...continued)
course of a decade cannot reasonably claim to have been in doubt as to
whether his use qualified as regular. See United States v. Purdy, 

,
812 (9th Cir. 2001) (“Purdy’s [regular, years-long] drug use … was sufficient
to put him on notice that he fell within the statutory definition of ‘unlawful
[drug] user.’”).
16                                                    No. 18-1343

by a doctor. See 

, 553 U.S. at 

.
    For these reasons, we are not convinced that Cook is
entitled to mount a facial vagueness challenge to section
922(g)(3). Johnson did not alter the general rule that a defendant
whose conduct is clearly prohibited by a statute cannot be the
one to make a facial vagueness challenge. United States v.
Westbrooks, 

, 325–26 (5th Cir. 2017) (collecting
cases), cert. granted & judgment vacated on other grounds, 

(2018). Cook’s conduct, if anything, undoubtedly
falls within the obvious core of conduct proscribed by the
statute. Per his statement at the police station, he had been
using marijuana daily for almost ten years and he had smoked
two blunts on the day of his arrest; and the police officers who
stopped his vehicle and took him into custody noted a strong
odor of marijuana emanating from the interior and that Cook
himself reeked of the substance. These facts no doubt explain
why Cook has declined to pursue an as-applied vagueness
challenge to section 922(g)(3): it would surely fail. See United
States v. Jackson, 

, 406 (4th Cir. 2002) (addressing
facts nearly identical to those presented here) (“While we do
not doubt that the exact reach of the statute is not easy to
define, we agree with the government that this is not a border-
line case. … Given the evidence, Jackson violated the plain
meaning of the statute.”).
    Cook’s attempt to challenge section 922(g)(3) as facially
vague fails for all of the reasons we have discussed, and
because he asserts no as-applied challenge to the statute, we
reject his contention that the statute is inconsistent with his due
process rights.
No. 18-1343                                                  17

B. Second Amendment
    Cook agrees that Yancey forecloses this challenge to section
922(g)(3). Yancey, as noted, held that there was a substantial
relationship between the government’s legitimate interest in
preventing violent crime and the statute’s ban on gun posses-
sion by unlawful drug 

–87. Although
Cook asserts that Yancey was wrongly decided, he offers us no
real reason to reconsider our precedent on this point. As the
law is settled in this circuit, we reject his Second Amendment
objection to the statute.
C. Jury Instruction
    Cook argues finally that the district court did not properly
instruct the jury as to the elements of his offense. As we noted
in our summary of the proceedings below, the court advised
the jury that “[t]he defendant was an unlawful user of mari-
juana if he used marijuana on a regular and ongoing basis for
a period of time that began before and continued through the
date of the offense.” R. 44 at 8; R. 56 at 70–71 (emphasis
omitted). The court added that Cook need not have been under
the influence of marijuana when he possessed a firearm, nor
was the government required to prove that he used marijuana
on any particular date or within a specified number of days of
the offense. (Recall that Cook had rejected the government’s
offer to add language that use of marijuana on a single occa-
sion was insufficient to establish unlawful drug use.) Cook
contends that the instruction as given was erroneous because
(a) it was not grounded in the language of section 922(g)(3);
(b) it was not consistent with Yancey’s holding as to who
constitutes an unlawful drug user; (c) the instruction was
18                                                   No. 18-1343

internally inconsistent; and (d) it foreclosed the defense from
urging the jurors to use their own understanding of “unlawful
user” in assessing Cook’s conduct. None of these arguments is
persuasive.
    The instruction was grounded in the language of the statute
in that it endeavored, consistent with the case law regarding
section 922(g)(3), to define for the jury who constitutes an
unlawful drug user. The statute itself does not define “unlaw-
ful drug user.” As discussed, this court in Yancey concluded
that an unlawful drug user is one who regularly uses a
controlled substance, other than as prescribed by a physician,
contemporaneously with possessing a 

,
687. In doing so, we acted in accord with other circuits which
have concluded that the statute’s reach is limited by two key
requirements: (1) regularity of drug use (2) that is sufficiently
contemporaneous with the possession of a firearm. See 

That these are limits imposed on the offense
by the judiciary rather than the face of the statute does not
render them invalid. See United States v. Lanier, 

,
266, 

, 1225 (1997) (“clarity at the requisite level
may be supplied by judicial gloss on an otherwise uncertain
statute”) (collecting cases); 

, 561 U.S. at 

–30 (before striking down a federal statute as
vague courts will first consider if it is subject to a limiting
construction that avoids vagueness); 

n.43 (“cases ‘paring down’ federal statutes to avoid
constitutional shoals are legion”). The district court appropri-
ately looked to Yancey’s gloss on the statute in defining
“unlawful drug user” for the jury.
No. 18-1343                                                     19

    Nor was the instruction inconsistent with Yancey. Cook
suggests that Yancey defined “unlawful user” of drugs to mean
either one who is addicted to controlled substances or one who
has simply used them within the past year, and that the
reference to “regular and ongoing” drug use in the district
court’s instruction is both broader than addiction and narrower
than use within the past year. But Cook’s reading of Yancey is
not a faithful reading of the court’s opinion. The opinion makes
clear that section 922(g)(3) requires regular or habitual drug 

, that is contemporaneous with the possession
of a firearm, 

Nowhere in our decision did we suggest
that a single or occasional, irregular use of a controlled
substance within a year of the gun possession was sufficient to
meet these criteria. Nor did we indicate that regular or habitual
use necessarily equates with addiction. The instruction given
here was fully consistent with Yancey’s requirements: the term
“regular” connotes a pattern of repeated drug use (be it
volitional or as the result of an addiction), and “ongoing”
connotes the requisite temporal nexus with possession of the
gun.
    The instruction was also internally consistent. Cook’s
contention to the contrary focuses on the fact that the instruc-
tion advised the jury, on the one hand, that his marijuana use
must have “beg[u]n before and continued through the date of
the charged offense” but, on the other hand, that he need not
have “used marijuana on any particular day, or within a
certain number of days of when he committed the charged
offense.” These portions of the instruction were not at odds
with one another. Consistent with Yancey’s requirement that
the defendant’s drug use be contemporaneous with his
20                                                 No. 18-1343

possession of a firearm, the court appropriately advised the
jury that Cook’s marijuana use must have been “ongoing” at
the time he was discovered in possession of a gun. But the
requirement that the drug use and firearm possession be
contemporaneous does not literally mean that the defendant
must have been ingesting (or under the influence of) a con-
trolled substance at the same time as he possessed the gun. The
statute, after all, prohibits firearm possession by a drug user,
not simply possession during drug use. So long as the defen-
dant was still engaged in the regular use of a drug at the time
of his firearm possession, it is not necessary to show that he
used the drug on the day of his firearm possession, the day
before, or within any particular number of days of the posses-
sion. Thus, a person who routinely uses marijuana on week-
ends may violate section 922(g)(3) by possessing a firearm on
a Tuesday or Wednesday, because his possession of the gun is
contemporaneous with his ongoing pattern of drug use. The
instruction appropriately and coherently advised the jury on
these points.
   Finally, we are no more persuaded than the district judge
was that the instruction should have left it to the jurors to
consult their own collective sense of who constitutes an
“unlawful user” of marijuana. Yancey establishes the relevant
parameters on this point, and the district court was required to
convey those parameters to the jury to guide its decisionmak-
ing, which Judge Peterson did admirably.
    That said, our holding should not be construed to foreclose
alternate versions of the “unlawful user” instruction. The Sixth
and Eighth Circuits, for example, have promulgated instruc-
tions with slightly different language. See MANUAL OF MODEL
No. 18-1343                                                    21

CRIMINAL JURY INSTRUCTIONS FOR THE DISTRICT COURTS OF THE
EIGHTH CIRCUIT § 6.18.922B, at 291–94 (2017); United States v.
Burchard, 

, 352 (6th Cir. 2009). Although the
arguments in this court and in the court below reflect some
anticipation that we might settle upon our own preferred
version of the instruction in this appeal, we respectfully decline
to do so. As the foregoing discussion makes clear, we find no
fault with the particular instruction that Judge Peterson gave
to the jury, and we need not go farther than that to resolve
Cook’s appeal. The task of drafting a model instruction, we
believe, is better left to our Circuit’s Pattern Criminal Jury
Instruction Committee, which has a membership that includes
practitioners as well as judges and which can solicit and
incorporate comments on any proposed instruction from the
bar at large. We shall invite the Committee to consider a
pattern instruction for a section 922(g)(3) charge, including but
not limited to the issue of who constitutes an “unlawful user”
of a controlled substance for purposes of this statute.
                              III.
   For all of the foregoing reasons, we AFFIRM Cook’s
conviction. We commend everyone involved in the briefing
and arguing of this case, along with Judge Peterson and
Magistrate Judge Crocker for their thorough and careful
handling of the case below. Their dedication and hard work
have greatly aided this court’s deliberation and resolution of
the appeal.