Cite as: 577 U. S. ____ (2016)            1

                             Per Curiam

SUPREME COURT OF THE UNITED STATES
        JAIME CAETANO v. MASSACHUSETTS
  ON PETITION FOR WRIT OF CERTIORARI TO THE SUPREME 

           JUDICIAL COURT OF MASSACHUSETTS

             No. 14–10078.    Decided March 21, 2016


  PER CURIAM.
  The Court has held that “the Second Amendment ex-
tends, prima facie, to all instruments that constitute
bearable arms, even those that were not in existence at
the time of the founding,” District of Columbia v. Heller,

, 582 (2008), and that this “Second Amend-
ment right is fully applicable to the States,” McDonald v.
Chicago, 

, 750 (2010). In this case, the Su-
preme Judicial Court of Massachusetts upheld a Massa-
chusetts law prohibiting the possession of stun guns after
examining “whether a stun gun is the type of weapon
contemplated by Congress in 1789 as being protected by
the Second Amendment.” 

, 777, 

, 691 (2015).
  The court offered three explanations to support its
holding that the Second Amendment does not extend to
stun guns. First, the court explained that stun guns are
not protected because they “were not in common use at the
time of the Second Amendment’s enactment.” 

26 N. E. 3d, at 693. This is inconsistent with Heller’s clear
statement that the Second Amendment “extends . . . to . . .
arms . . . that were not in existence at the time of the

.
  The court next asked whether stun guns are “dangerous
per se at common law and 

, 26
N. E. 3d, at 694, in an attempt to apply one “important
limitation on the right to keep and carry arms,” 

; see 

historical
tradition of prohibiting the carrying of ‘dangerous and
2              CAETANO v. MASSACHUSETTS

                         Per Curiam

unusual weapons’ ”). In so doing, the court concluded that
stun guns are “unusual” because they are “a thoroughly
modern invention.” 470 Mass., at 

–694. By equating “unusual” with “in common use at
the time of the Second Amendment’s enactment,” the
court’s second explanation is the same as the first; it is
inconsistent with Heller for the same reason.
   Finally, the court used “a contemporary lens” and found
“nothing in the record to suggest that [stun guns] are
readily adaptable to use in the military.” 470 Mass., at

. But Heller rejected the proposi-
tion “that only those weapons useful in warfare are pro-

–625.
   For these three reasons, the explanation the Massachu-
setts court offered for upholding the law contradicts this
Court’s precedent. Consequently, the petition for a writ of
certiorari and the motion for leave to proceed in forma
pauperis are granted. The judgment of the Supreme
Judicial Court of Massachusetts is vacated, and the case is
remanded for further proceedings not inconsistent with
this opinion.
                                            It is so ordered.
                 Cite as: 577 U. S. ____ (2016)            1

                ALITO, J., concurring in judgment

SUPREME COURT OF THE UNITED STATES
        JAIME CAETANO v. MASSACHUSETTS
  ON PETITION FOR WRIT OF CERTIORARI TO THE SUPREME 

           JUDICIAL COURT OF MASSACHUSETTS

             No. 14–10078.   Decided March 21, 2016


  JUSTICE ALITO, with whom JUSTICE THOMAS joins,
concurring in the judgment.
  After a “bad altercation” with an abusive boyfriend put
her in the hospital, Jaime Caetano found herself homeless
and “in fear for [her] life.” Tr. 31, 38 (July 10, 2013). She
obtained multiple restraining orders against her abuser,
but they proved futile. So when a friend offered her a stun
gun “for self-defense against [her] former boy friend,” 

, 776, 

, 690 (2015), Caetano
accepted the weapon.
  It is a good thing she did. One night after leaving work,
Caetano found her ex-boyfriend “waiting for [her] outside.”
Tr. 35. He “started screaming” that she was “not gonna
[expletive deleted] work at this place” any more because
she “should be home with the kids” they had together.

over her by nearly a foot
and outweighed her by close to 100 pounds. But she didn’t
need physical strength to protect herself. She stood her
ground, displayed the stun gun, and announced: “I’m not
gonna take this anymore. . . . I don’t wanna have to [use
the stun gun on] you, but if you don’t leave me alone, I’m
gonna have to.” 

The gambit worked. The
ex-boyfriend “got scared and he left [her] alone.” 

  It is settled that the Second Amendment protects an
individual right to keep and bear arms that applies
against both the Federal Government and the States.
District of Columbia v. Heller, 

(2008);
McDonald v. Chicago, 

(2010). That right
2              CAETANO v. MASSACHUSETTS

               ALITO, J., concurring in judgment

vindicates the “basic right” of “individual self-defense.”

see 

, 628. Caetano’s en­
counter with her violent ex-boyfriend illustrates the con­
nection between those fundamental rights: By arming
herself, Caetano was able to protect against a physical
threat that restraining orders had proved useless to pre­
vent. And, commendably, she did so by using a weapon
that posed little, if any, danger of permanently harming
either herself or the father of her children.
  Under Massachusetts law, however, Caetano’s mere
possession of the stun gun that may have saved her life
made her a criminal. See Mass. Gen. Laws, ch. 140, §131J
(2014). When police later discovered the weapon, she was
arrested, tried, and convicted. The Massachusetts Su­
preme Judicial Court affirmed the conviction, holding that
a stun gun “is not the type of weapon that is eligible for
Second Amendment protection” because it was “not in
common use at the time of [the Second Amendment’s]
enactment.” 470 Mass., at 

.
  This reasoning defies our decision in Heller, which
rejected as “bordering on the frivolous” the argument “that
only those arms in existence in the 18th century are pro­
tected by the Second 

. The
decision below also does a grave disservice to vulnerable
individuals like Caetano who must defend themselves
because the State will not.
                             I
  The events leading to Caetano’s prosecution occurred
sometime after the confrontation between her and her ex-
boyfriend. In September 2011, police officers responded to
a reported shoplifting at an Ashland, Massachusetts,
supermarket. The store’s manager had detained a sus­
pect, but he identified Caetano and another person in the
parking lot as potential accomplices. Police approached
the two and obtained Caetano’s consent to search her
                     Cite as: 577 U. S. ____ (2016)                     3

                   ALITO, J., concurring in judgment

purse. They found no evidence of shoplifting, but saw
Caetano’s stun gun. Caetano explained to the officers that
she had acquired the weapon to defend herself against a
violent ex-boyfriend.
   The officers believed Caetano, but they arrested her for
violating Mass. Gen. Laws, ch. 140, §131J, “which bans
entirely the possession of an electrical 

, 26 N. E. 3d, at 689.1 When Caetano moved
to dismiss the charge on Second Amendment grounds, the
trial court denied the motion.
   A subsequent bench trial established the following
undisputed facts. The parties stipulated that Caetano
possessed the stun gun and that the weapon fell within
the statute’s prohibition.2 The Commonwealth also did
not challenge Caetano’s testimony that she possessed the
weapon to defend herself against the violent ex-boyfriend.
Indeed, the prosecutor urged the court “to believe the
defendant.” Tr. 40. The trial court nonetheless found

——————
  1 Specifically, the statute prohibits the possession of any “portable

device or weapon from which an electrical current, impulse, wave or
beam may be directed, which current, impulse, wave or beam is de­
signed to incapacitate temporarily, injure or kill.” Mass. Gen. Laws,
ch. 140, §131J (2014).      The statute includes exceptions for law-
enforcement officers and weapon suppliers, who may possess electrical
weapons “designed to incapacitate temporarily.” 

by a fine of $500 to $1,000, imprisonment of 6 months to 2½
years, or both. 

like Caetano’s “are designed to stun a person with an

electrical current” by running a current between two metal prongs on
the device and placing the prongs in direct contact with the person. 

, 775, n. 2, 

, 689, n. 2 (2015). A similar device,
popularly known by the brand name “Taser,” shoots out wires tipped
with electrodes that can deliver an electrical current from a distance.
Tr. 25–26. Tasers can also be used like a stun gun without deploying
the electrodes—a so-called “dry stun.” 

As the Common­
wealth’s witness testified at trial, these sorts of electrical weapons are
“non-lethal force” “designed to incapacitate”—“not kill”—a target. 

4                  CAETANO v. MASSACHUSETTS

                   ALITO, J., concurring in judgment

Caetano guilty, and she appealed to the Massachusetts
Supreme Judicial Court.
   The Supreme Judicial Court rejected Caetano’s Second
Amendment claim, holding that “a stun gun is not the type
of weapon that is eligible for Second Amendment protec­
tion.” 470 Mass., at 

. The court
reasoned that stun guns are unprotected because they
were “not ‘in common use at the time’ of enactment of the
Second Amendment,” id., at 

(quot­
ing 

), and because they fall within the
“traditional prohibition against carrying dangerous and
unusual 

, 26 N. E. 3d, at 692
(citing 

).
                              II
 Although the Supreme Judicial Court professed to apply
Heller, each step of its analysis defied Heller’s reasoning.
                             A
  The state court repeatedly framed the question before it
as whether a particular weapon was “ ‘in common use at
the time’ of enactment of the Second Amendment.” 470
Mass., at 

; see also 

780,

, 693, 694. In Heller, we emphati­
cally rejected such a formulation. We found the argument
“that only those arms in existence in the 18th century are
protected by the Second Amendment” not merely wrong,
but “bordering on the 

. In­
stead, we held that “the Second Amendment extends,
prima facie, to all instruments that constitute bearable
arms, even those that were not in existence at the time of
the founding.” 

is hard to
——————
    3 Stun
         guns are plainly “bearable arms.” As Heller explained, the
term includes any “[w]eapo[n] of offence” or “thing that a man wears for
his defence, or takes into his hands,” that is “carr[ied] . . . for the
purpose of offensive or defensive 

, 584 (inter­
                     Cite as: 577 U. S. ____ (2016)                    5

                   ALITO, J., concurring in judgment

imagine language speaking more directly to the point. Yet
the Supreme Judicial Court did not so much as mention it.
   Instead, the court seized on language, originating in
United States v. Miller, 

(1939), that “ ‘the
sorts of weapons protected were those “in common use at
the time.” ’ 

, 26 N. E. 3d, at 692 (quot­
ing 

, in turn quoting 

). That quotation does not mean, as the court below
thought, that only weapons popular in 1789 are covered by
the Second Amendment. It simply reflects the reality that
the founding-era militia consisted of citizens “who would
bring the sorts of lawful weapons that they possessed at
home to militia duty,” 

, and that
the Second Amendment accordingly guarantees the right
to carry weapons “typically possessed by law-abiding
citizens for lawful purposes,” 

While stun guns
were not in existence at the end of the 18th century, the
same is true for the weapons most commonly used today
for self-defense, namely, revolvers and semiautomatic
pistols. Revolvers were virtually unknown until well into
the 19th century,4 and semiautomatic pistols were not
invented until near the end of that century.5 Electronic
stun guns are no more exempt from the Second Amend­
ment’s protections, simply because they were unknown to
the First Congress, than electronic communications are
exempt from the First Amendment, or electronic imaging
devices are exempt from the Fourth Amendment. 

(citing Reno v. American Civil Liberties Union, 521
——————
nal quotation marks omitted).
  4 See J. Bilby, A Revolution in Arms: A History of the First Repeating

Rifles 23 (2006). Samuel Colt did not patent his famous revolver until
1836. 

An Illustrated History 166 (2014); see also W. Greener,

The Gun and Its Development 524–529, 531–534 (9th ed. 1910) (dis­
cussing revolvers and self-loading semiautomatic pistols as “modern
pistols”).
6              CAETANO v. MASSACHUSETTS

                ALITO, J., concurring in judgment

U. S. 844, 849 (1997), and Kyllo v. United States, 

, 35–36 (2001)). As Heller aptly put it: “We do not inter­
pret constitutional rights that 

.
                             B
   The Supreme Judicial Court’s holding that stun guns
may be banned as “dangerous and unusual weapons” fares
no better. As the per curiam opinion recognizes, this is a
conjunctive test: A weapon may not be banned unless it is
both dangerous and unusual. Because the Court rejects
the lower court’s conclusion that stun guns are “unusual,”
it does not need to consider the lower court’s conclusion
that they are also “dangerous.” See ante, at 1–2. But
make no mistake—the decision below gravely erred on
both grounds.
                               1
  As to “dangerous,” the court below held that a weapon is
“dangerous per se” if it is “ ‘designed and constructed to
produce death or great bodily harm’ and ‘for the purpose of
bodily assault or defense.’ ” 470 Mass., at 

(quoting Commonwealth v. Appleby, 

,
303, 

, 1056 (1980)). That test may be
appropriate for applying statutes criminalizing assault
with a dangerous weapon. See 

.
But it cannot be used to identify arms that fall outside the
Second Amendment. First, the relative dangerousness of
a weapon is irrelevant when the weapon belongs to a class
of arms commonly used for lawful purposes. See 

(contrasting “ ‘dangerous and unusual weap­
ons’ ” that may be banned with protected “weapons . . . ‘in
common use at the time’ ”). Second, even in cases where
dangerousness might be relevant, the Supreme Judicial
Court’s test sweeps far too broadly. Heller defined the
“Arms” covered by the Second Amendment to include “ ‘any
thing that a man wears for his defence, or takes into his
                 Cite as: 577 U. S. ____ (2016)            7

                ALITO, J., concurring in judgment

hands, or useth in wrath to cast at or strike another.’ 

. Under the decision below, however,
virtually every covered arm would qualify as “dangerous.”
   Were there any doubt on this point, one need only look
at the court’s first example of “dangerous per se” weapons:
“firearms.” 470 Mass., at 

. If
Heller tells us anything, it is that firearms cannot be
categorically prohibited just because they are 

. A fortiori, stun guns that the Common­
wealth’s own witness described as “non-lethal force,” Tr.
27, cannot be banned on that basis.
                              2
  The Supreme Judicial Court’s conclusion that stun guns
are “unusual” rested largely on its premise that one must
ask whether a weapon was commonly used in 1789. 

–

–694. As al­
ready discussed, that is simply wrong. 

–6.
  The court also opined that a weapon’s unusualness
depends on whether “it is a weapon of warfare to be used
by the 

, 26 N. E. 3d, at 693. It
asserted that we followed such an approach in Miller and
“approved its use in Heller.” 470 Mass., at 

. But Heller actually said that it would be
a “startling reading” of Miller to conclude that “only those
weapons useful in warfare are pro

. Instead, Miller and Heller recognized that militia
members traditionally reported for duty carrying “the
sorts of lawful weapons that they possessed at home,” and
that the Second Amendment therefore protects such
weapons as a class, regardless of any particular weapon’s
suitability for military 

; see 

Indeed, Heller acknowledged that advancements
in military technology might render many commonly
owned weapons ineffective in warfare. 

But such “modern developments . . . cannot change our
8               CAETANO v. MASSACHUSETTS

                 ALITO, J., concurring in judgment

interpretation of the right.” 

the Supreme Judicial Court’s assumption
that stun guns are unsuited for militia or military use is
untenable. Section 131J allows law enforcement and
correctional officers to carry stun guns and Tasers, pre­
sumably for such purposes as nonlethal crowd control.
Subduing members of a mob is little different from “sup­
press[ing] Insurrections,” a traditional role of the militia.
U. S. Const., Art. I, §8, cl. 15; see also 

called forth “to execute the Laws of the Union”). Addition­
ally, several branches of the U. S. armed services equip
troops with electrical stun weapons to “incapacitate a
target without permanent injury or known side effects.”
U. S. Army, Project Manager Close Combat Systems, PD
Combat Munitions: Launched Electrode Stun Device
(LESD), http://www.pica.army.mil/pmccs/combatmunitions/
nonlethalsys/taserx26e.html (all Internet materials as last
visited Mar. 18, 2016); see U. S. Marine Corps Admin-
istrative Message 560/08 (Oct. 2, 2008) (Marine Corps
guidance for use of Tasers), http://www.marines.mil/
News / Messages /MessagesDisplay/tabid/13286/Article/1130
24/marine-corps-training-and-use-of-human-electro-muscular­
incapacitation-hemi-dev.aspx; Joint Non-Lethal Weapons
Directorate, Non-Lethal Weapons (NLW) Reference Book
3 (2012) (Department of Defense report stating that
“[m]ultiple Services employ” Tasers), http://dtic.mil/dtic/
tr/fulltext/u2/a565971.pdf.
                            C
  As the foregoing makes clear, the pertinent Second
Amendment inquiry is whether stun guns are commonly
possessed by law-abiding citizens for lawful purposes
today. The Supreme Judicial Court offered only a cursory
discussion of that question, noting that the “ ‘number of
Tasers and stun guns is dwarfed by the number of fire­
arms.’ ” 470 Mass., at 

. This ob­
                 Cite as: 577 U. S. ____ (2016)           9

               ALITO, J., concurring in judgment

servation may be true, but it is beside the point. Other­
wise, a State would be free to ban all weapons except
handguns, because “handguns are the most popular weapon
chosen by Americans for self-defense in the home.” 

.
   The more relevant statistic is that “[h]undreds of thou­
sands of Tasers and stun guns have been sold to private
citizens,” who it appears may lawfully possess them in 45
States. People v. Yanna, 

, 144, 

, 245 (2012) (holding Michigan stun gun ban
unconstitutional); see Volokh, Nonlethal Self-Defense,
(Almost Entirely) Nonlethal Weapons, and the Rights To
Keep and Bear Arms and Defend Life, 62 Stan. L. Rev.
199, 244 (2009) (citing stun gun bans in seven States);
Wis. Stat. §941.295 (Supp. 2015) (amended Wisconsin law
permitting stun gun possession); see also Brief in Opposi­
tion 11 (acknowledging that “approximately 200,000 civil­
ians owned stun guns” as of 2009). While less popular
than handguns, stun guns are widely owned and accepted
as a legitimate means of self-defense across the country.
Massachusetts’ categorical ban of such weapons therefore
violates the Second Amendment.
                            III
  The lower court’s ill treatment of Heller cannot stand.
The reasoning of the Massachusetts court poses a grave
threat to the fundamental right of self-defense. The Su­
preme Judicial Court suggested that Caetano could have
simply gotten a firearm to defend 

, 26 N. E. 3d, at 695. But the right to bear other weap­
ons is “no answer” to a ban on the possession of protected
arms. 

. Moreover, a weapon is an
effective means of self-defense only if one is prepared to
use it, and it is presumptuous to tell Caetano she should
have been ready to shoot the father of her two young
children if she wanted to protect herself. Courts should
10                CAETANO v. MASSACHUSETTS

                   ALITO, J., concurring in judgment

not be in the business of demanding that citizens use more
force for self-defense than they are comfortable wielding.6
  Countless people may have reservations about using
deadly force, whether for moral, religious, or emotional
reasons—or simply out of fear of killing the wrong person.
See Brief for Arming Women Against Rape & Endanger­
ment as Amicus Curiae 4–5. “Self-defense,” however, “is a
basic right.” 

. I am not pre­
pared to say that a State may force an individual to choose
between exercising that right and following her con­
science, at least where both can be accommodated by a
weapon already in widespread use across the Nation.
                        *     *     *
   A State’s most basic responsibility is to keep its people
safe. The Commonwealth of Massachusetts was either
unable or unwilling to do what was necessary to protect
Jaime Caetano, so she was forced to protect herself. To
make matters worse, the Commonwealth chose to deploy
its prosecutorial resources to prosecute and convict her of
a criminal offense for arming herself with a nonlethal
weapon that may well have saved her life. The Supreme
Judicial Court then affirmed her conviction on the flimsi­
est of grounds. This Court’s grudging per curiam now
sends the case back to that same court. And the conse­
quences for Caetano may prove more tragic still, as her
conviction likely bars her from ever bearing arms for self-
defense. See Pet. for Cert. 14.
   If the fundamental right of self-defense does not protect
Caetano, then the safety of all Americans is left to the
mercy of state authorities who may be more concerned
about disarming the people than about keeping them safe.
——————
  6 The court below also noted that Massachusetts no longer requires a
license to possess mace or pepper spray. 470 Mass., at 

. But the law was changed in 2014, after Caetano was convicted.
A spray can also be foiled by a stiff breeze, while a stun gun cannot.