(Slip Opinion)              OCTOBER TERM, 2013                                       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., 200 U. S. 321, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

                 ROSEMOND v. UNITED STATES

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
                 THE TENTH CIRCUIT

   No. 12–895.      Argued November 12, 2013—Decided March 5, 2014
Petitioner Justus Rosemond took part in a drug deal in which either he
  or one of his confederates fired a gun. Because the shooter’s identity
  was disputed, the Government charged Rosemond with violating 18
  U. S. C. §924(c) by using or carrying a gun in connection with a drug
  trafficking crime, or, in the alternative, aiding and abetting that of-
  fense under 18 U. S. C. §2. The trial judge instructed the jury that
  Rosemond was guilty of aiding and abetting the §924(c) offense if he
  (1) “knew his cohort used a firearm in the drug trafficking crime” and
  (2) “knowingly and actively participated in the drug trafficking
  crime.” This deviated from Rosemond’s proposed instruction that the
  jury must find that he acted intentionally “to facilitate or encourage”
  the firearm’s use, as opposed to merely the predicate drug offense.
  Rosemond was convicted, and the Tenth Circuit affirmed, rejecting
  his argument that the District Court’s aiding and abetting instruc-
  tions were erroneous.
Held:
    1. The Government establishes that a defendant aided and abetted
 a §924(c) violation by proving that the defendant actively participat-
 ed in the underlying drug trafficking or violent crime with advance
 knowledge that a confederate would use or carry a gun during the
 crime’s commission. Pp. 5–16.
       (a) The federal aiding and abetting statute, which derives from
 common-law standards for accomplice liability, has two components.
 A person is liable under §2 only if he (1) takes an affirmative act in
 furtherance of the underlying offense (2) with the intent to facilitate
 that offense’s commission. Pp. 5–6.
       (b) The first question is whether Rosemond’s conduct was suffi-
 cient to satisfy the affirmative act requirement of aiding and abet-
2                    ROSEMOND v. UNITED STATES

                                  Syllabus

    ting. Section 924(c) has two elements: a drug deal or violent crime,
    and using or carrying a firearm in connection with that crime. The
    instructions permitted the jury to convict Rosemond of aiding and
    abetting even if he facilitated only the drug element, and not the gun
    element, of the §924(c) offense. Those instructions were correct. The
    common law imposed aiding and abetting liability on a person who
    facilitated any element of a criminal offense, even if he did not facili-
    tate all elements. That principle continues to govern §2. See, e.g.,
    United States v. Johnson, 319 U. S. 503, 515. Pp. 6–11.
         (c) In addition to conduct extending to some part of the crime,
    aiding and abetting requires intent extending to the whole crime.
    The defendant must not just associate himself with the venture, but
    also participate in it as something that he wishes to bring about and
    seek by his actions to make it succeed. Nye & Nissen v. United
    States, 336 U. S. 613, 619. That requirement is satisfied when a per-
    son actively participates in a criminal venture with full knowledge of
    the circumstances constituting the charged offense. See Pereira v.
    United States, 347 U. S. 1, 12. An active participant in a drug trans-
    action has the intent needed to aid and abet a §924(c) violation when
    he knows that one of his confederates will carry a gun. This must be
    advance knowledge—meaning, knowledge at a time when the accom-
    plice has a reasonable opportunity to walk away. Pp. 11–16.
      2. The trial court’s jury instructions were erroneous because they
    failed to require that Rosemond knew in advance that one of his co-
    horts would be armed. In telling the jury to consider merely whether
    Rosemond “knew his cohort used a firearm,” the court did not direct
    the jury to determine when Rosemond obtained the requisite
    knowledge—i.e., to decide whether Rosemond knew about the gun in
    sufficient time to withdraw from the crime. The case is remanded to
    permit the Tenth Circuit to address whether this objection was
    properly preserved and whether any error was harmless. Pp. 16–19.
695 F. 3d 1151, vacated and remanded.

   KAGAN, J., delivered the opinion of the Court, in which ROBERTS,
C. J., and KENNEDY, GINSBURG, BREYER, and SOTOMAYOR, JJ., joined,
and in which SCALIA, J., joined in all but footnotes 7 and 8. ALITO, J.,
filed an opinion concurring in part and dissenting in part, in which
THOMAS, J., joined.
                        Cite as: 572 U. S. ____ (2014)                              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. 12–895
                                   _________________


         JUSTUS C. ROSEMOND, PETITIONER v.

                   UNITED STATES

 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF 

            APPEALS FOR THE TENTH CIRCUIT

                                 [March 5, 2014] 


   JUSTICE KAGAN delivered the opinion of the Court.*
   A federal criminal statute, §924(c) of Title 18, prohibits
“us[ing] or carr[ying]” a firearm “during and in relation to
any crime of violence or drug trafficking crime.” In this
case, we consider what the Government must show when
it accuses a defendant of aiding or abetting that offense.
We hold that the Government makes its case by proving
that the defendant actively participated in the underlying
drug trafficking or violent crime with advance knowledge
that a confederate would use or carry a gun during the
crime’s commission. We also conclude that the jury in-
structions given below were erroneous because they failed
to require that the defendant knew in advance that one of
his cohorts would be armed.
                           I
  This case arises from a drug deal gone bad. Vashti
Perez arranged to sell a pound of marijuana to Ricardo
Gonzales and Coby Painter. She drove to a local park to
make the exchange, accompanied by two confederates,
——————
 * JUSTICE SCALIA joins all but footnotes 7 and 8 of this opinion.
2                 ROSEMOND v. UNITED STATES

                         Opinion of the Court

Ronald Joseph and petitioner Justus Rosemond. One of
those men apparently took the front passenger seat and
the other sat in the back, but witnesses dispute who was
where. At the designated meeting place, Gonzales climbed
into the car’s backseat while Painter waited outside. The
backseat passenger allowed Gonzales to inspect the mari-
juana. But rather than handing over money, Gonzales
punched that man in the face and fled with the drugs. As
Gonzales and Painter ran away, one of the male passengers—
but again, which one is contested—exited the car and
fired several shots from a semiautomatic handgun. The
shooter then re-entered the vehicle, and all three would-
be drug dealers gave chase after the buyers-turned-
robbers. But before the three could catch their quarry,
a police officer, responding to a dispatcher’s alert, pulled
their car over. This federal prosecution of Rosemond
followed.1
   The Government charged Rosemond with, inter alia,
violating §924(c) by using a gun in connection with a drug
trafficking crime, or aiding and abetting that offense
under §2 of Title 18. Section 924(c) provides that “any
person who, during and in relation to any crime of violence
or drug trafficking crime[,] . . . uses or carries a firearm,”
shall receive a five-year mandatory-minimum sentence,
with seven- and ten-year minimums applicable, respec-
tively, if the firearm is also brandished or discharged. 18
U. S. C. §924(c)(1)(A). Section 2, for its part, is the federal
aiding and abetting statute: It provides that “[w]hoever
commits an offense against the United States or aids,
abets, counsels, commands, induces or procures its com-
mission is punishable as a principal.”
   Consistent with the indictment, the Government prose-
——————
  1 The Government agreed not to bring charges against the other four

participants in the narcotics deal in exchange for their giving truthful
testimony against Rosemond. See 2 Record 245, 272, 295–296, 318.
                  Cite as: 572 U. S. ____ (2014)            3

                      Opinion of the Court

cuted the §924(c) charge on two alternative theories. The
Government’s primary contention was that Rosemond
himself used the firearm during the aborted drug transac-
tion. But recognizing that the identity of the shooter was
disputed, the Government also offered a back-up argu-
ment: Even if it was Joseph who fired the gun as the drug
deal fell apart, Rosemond aided and abetted the §924(c)
violation.
   The District Judge accordingly instructed the jury on
aiding and abetting law. He first explained, in a way
challenged by neither party, the rudiments of §2. Under
that statute, the judge stated, “[a] person who aids or
abets another to commit an offense is just as guilty of that
offense as if he committed it himself.” App. 195. And in
order to aid or abet, the defendant must “willfully and
knowingly associate[ ] himself in some way with the crime,
and . . . seek[ ] by some act to help make the crime suc-
ceed.” Id., at 196. The judge then turned to applying
those general principles to §924(c)—and there, he deviated
from an instruction Rosemond had proposed. According to
Rosemond, a defendant could be found guilty of aiding or
abetting a §924(c) violation only if he “intentionally took
some action to facilitate or encourage the use of the fire-
arm,” as opposed to the predicate drug offense. Id., at 14.
But the District Judge disagreed, instead telling the jury
that it could convict if “(1) the defendant knew his cohort
used a firearm in the drug trafficking crime, and (2) the
defendant knowingly and actively participated in the drug
trafficking crime.” Id., at 196. In closing argument, the
prosecutor contended that Rosemond easily satisfied that
standard, so that even if he had not “fired the gun, he’s
still guilty of the crime.” Id., at 158. After all, the prose-
cutor stated, Rosemond “certainly knew [of] and actively
participated in” the drug transaction. Ibid. “And with
regards to the other element,” the prosecutor urged, “the
fact is a person cannot be present and active at a drug deal
4                 ROSEMOND v. UNITED STATES

                         Opinion of the Court

when shots are fired and not know their cohort is using a
gun. You simply can’t do it.” Ibid.
   The jury convicted Rosemond of violating §924(c) (as
well as all other offenses charged). The verdict form was
general: It did not reveal whether the jury found that
Rosemond himself had used the gun or instead had aided
and abetted a confederate’s use during the marijuana deal.
As required by §924(c), the trial court imposed a consec-
utive sentence of 120 months of imprisonment for the
statute’s violation.
   The Tenth Circuit affirmed, rejecting Rosemond’s argu-
ment that the District Court’s aiding and abetting instruc-
tions were erroneous.2 The Court of Appeals acknowledged
that some other Circuits agreed with Rosemond that
a defendant aids and abets a §924(c) offense only if he
intentionally takes “some action to facilitate or encourage
his cohort’s use of the firearm.” 695 F. 3d 1151, 1155
(2012).3 But the Tenth Circuit had already adopted a
different standard, which it thought consonant with the
District Court’s instructions. See, e.g., United States v.
Wiseman, 172 F. 3d 1196, 1217 (1999) (requiring that the
defendant “actively participated in the” underlying crime
and “knew [his confederate] was carrying [a] firearm”).
And the Court of Appeals held that Rosemond had pre-
sented no sufficient reason for departing from that prece-
dent. See 695 F. 3d, at 1156.
   We granted certiorari, 569 U. S. ___ (2013), to resolve

——————
   2 The Court of Appeals stated that it had to address that argument

even if the jury could have found that Rosemond himself fired the gun,
because “a conviction based on a general verdict is subject to challenge
if the jury was instructed on alternative theories of guilt and may have
relied on an invalid one.” 695 F. 3d 1151, 1154 (2012) (quoting
Hedgpeth v. Pulido, 555 U. S. 57, 58 (2008) (per curiam)).
   3 See, e.g., United States v. Rolon-Ramos, 502 F. 3d 750, 758–759

(CA8 2007); United States v. Medina-Roman, 376 F. 3d 1, 6 (CA1 2004);
United States v. Bancalari, 110 F. 3d 1425, 1429–1430 (CA9 1997).
                 Cite as: 572 U. S. ____ (2014)            5

                     Opinion of the Court

the Circuit conflict over what it takes to aid and abet a
§924(c) offense. Although we disagree with Rosemond’s
principal arguments, we find that the trial court erred in
instructing the jury. We therefore vacate the judgment
below.
                              II
  The federal aiding and abetting statute, 18 U. S. C. §2,
states that a person who furthers—more specifically, who
“aids, abets, counsels, commands, induces or procures”—
the commission of a federal offense “is punishable as a
principal.” That provision derives from (though simplifies)
common-law standards for accomplice liability. See, e.g.,
Standefer v. United States, 447 U. S. 10, 14–19 (1980);
United States v. Peoni, 100 F. 2d 401, 402 (CA2 1938)
(L. Hand, J.) (“The substance of [§2’s] formula goes back
a long way”). And in so doing, §2 reflects a centuries-old
view of culpability: that a person may be responsible for a
crime he has not personally carried out if he helps another
to complete its commission. See J. Hawley & M. McGregor,
Criminal Law 81 (1899).
  We have previously held that under §2 “those who pro-
vide knowing aid to persons committing federal crimes,
with the intent to facilitate the crime, are themselves
committing a crime.” Central Bank of Denver, N. A. v.
First Interstate Bank of Denver, N. A., 511 U. S. 164, 181
(1994). Both parties here embrace that formulation, and
agree as well that it has two components. See Brief for
Petitioner 28; Brief for United States 14. As at common
law, a person is liable under §2 for aiding and abetting a
crime if (and only if) he (1) takes an affirmative act in
furtherance of that offense, (2) with the intent of facili-
tating the offense’s commission. See 2 W. LaFave, Sub-
stantive Criminal Law §13.2, p. 337 (2003) (hereinafter
LaFave) (an accomplice is liable as a principal when he gives
“assistance or encouragement . . . with the intent thereby
6              ROSEMOND v. UNITED STATES

                     Opinion of the Court

to promote or facilitate commission of the crime”); Hicks v.
United States, 150 U. S. 442, 449 (1893) (an accomplice is
liable when his acts of assistance are done “with the inten-
tion of encouraging and abetting” the crime).
   The questions that the parties dispute, and we here
address, concern how those two requirements—affirmative
act and intent—apply in a prosecution for aiding and
abetting a §924(c) offense. Those questions arise from the
compound nature of that provision. Recall that §924(c)
forbids “us[ing] or carr[ying] a firearm” when engaged in a
“crime of violence or drug trafficking crime.” See supra, at
2. The prosecutor must show the use or carriage of a gun;
so too he must prove the commission of a predicate (violent
or drug trafficking) offense. See Smith v. United States,
508 U. S. 223, 228 (1993). For purposes of ascertaining
aiding and abetting liability, we therefore must consider:
When does a person act to further this double-barreled
crime? And when does he intend to facilitate its commis-
sion? We address each issue in turn.
                               A
   Consider first Rosemond’s account of his conduct (di-
vorced from any issues of intent). Rosemond actively par-
ticipated in a drug transaction, accompanying two others
to a site where money was to be exchanged for a pound
of marijuana. But as he tells it, he took no action
with respect to any firearm. He did not buy or borrow a
gun to facilitate the narcotics deal; he did not carry a gun
to the scene; he did not use a gun during the subsequent
events constituting this criminal misadventure. His acts thus
advanced one part (the drug part) of a two-part incident—
or to speak a bit more technically, one element (the
drug element) of a two-element crime. Is that enough to
satisfy the conduct requirement of this aiding and abetting
charge, or must Rosemond, as he claims, have taken some
act to assist the commission of the other (firearm) compo-
                     Cite as: 572 U. S. ____ (2014)                    7

                          Opinion of the Court

nent of §924(c)?
   The common law imposed aiding and abetting liability
on a person (possessing the requisite intent) who facili-
tated any part—even though not every part—of a criminal
venture. As a leading treatise, published around the time
of §2’s enactment, put the point: Accomplice liability at-
tached upon proof of “[a]ny participation in a general
felonious plan” carried out by confederates. 1 F. Wharton,
Criminal Law §251, p. 322 (11th ed. 1912) (hereinafter
Wharton) (emphasis added). Or in the words of another
standard reference: If a person was “present abetting
while any act necessary to constitute the offense [was]
being performed through another,” he could be charged as
a principal—even “though [that act was] not the whole
thing necessary.” 1 J. Bishop, Commentaries on the Crim-
inal Law §649, p. 392 (7th ed. 1882) (emphasis added).
And so “[w]here several acts constitute[d] together one
crime, if each [was] separately performed by a different
individual[,] . . . all [were] principals as to the whole.” Id.,
§650, at 392.4 Indeed, as yet a third treatise underscored,
a person’s involvement in the crime could be not merely
partial but minimal too: “The quantity [of assistance was]
immaterial,” so long as the accomplice did “something” to
aid the crime. R. Desty, A Compendium of American
Criminal Law §37a, p. 106 (1882) (emphasis added). After
all, the common law maintained, every little bit helps—
and a contribution to some part of a crime aids the whole.

——————
  4 The Wharton treatise gave the following example of how multiple

confederates could perform different roles in carrying out a crime.
Assume, Wharton hypothesized, that several persons “act in concert to
steal a man’s goods.” Wharton §251, at 322. The victim is “induced by
fraud to trust one of them[,] in the presence of [the] others[,] with the
[goods’] possession.” Ibid. Afterward, “another of the party entice[s]
the owner away so that he who has the goods may carry them off.” Id.,
at 322–323. Wharton concludes: “[A]ll are guilty as principals.” Id.,
at 323.
8                  ROSEMOND v. UNITED STATES

                          Opinion of the Court

   That principle continues to govern aiding and abetting
law under §2: As almost every court of appeals has held,
“[a] defendant can be convicted as an aider and abettor
without proof that he participated in each and every ele-
ment of the offense.” United States v. Sigalow, 812 F. 2d
783, 785 (CA2 1987).5 In proscribing aiding and abetting,
Congress used language that “comprehends all assistance
rendered by words, acts, encouragement, support, or pres-
ence,” Reves v. Ernst & Young, 507 U. S. 170, 178 (1993)—
even if that aid relates to only one (or some) of a crime’s
phases or elements. So, for example, in upholding convic-
tions for abetting a tax evasion scheme, this Court found
“irrelevant” the defendants’ “non-participation” in filing a
false return; we thought they had amply facilitated the
illegal scheme by helping a confederate conceal his assets.
United States v. Johnson, 319 U. S. 503, 515, 518 (1943).
“[A]ll who shared in [the overall crime’s] execution,” we
explained, “have equal responsibility before the law, what-
ever may have been [their] different roles.” Id., at 515.
And similarly, we approved a conviction for abetting mail
fraud even though the defendant had played no part in
mailing the fraudulent documents; it was enough to sat-
isfy the law’s conduct requirement that he had in other
ways aided the deception. See Pereira v. United States,
347 U. S. 1, 8–11 (1954). The division of labor between
two (or more) confederates thus has no significance: A
strategy of “you take that element, I’ll take this one”
——————
   5 See also United States v. Ali, 718 F. 3d 929, 939 (CADC 2013)

(“[P]roving a defendant guilty of aiding and abetting does not ordinarily
require the government to establish participation in each . . . element of
the underlying offense”); United States v. Arias-Izquierdo, 449 F. 3d
1168, 1176 (CA11 2006) (“The government was not required to prove
that [the defendant] participated in each element of the substantive
offense in order to hold him liable as an aider and abettor”); United
States v. Woods, 148 F. 3d 843, 850 (CA7 1998) (“[T]he government
need not prove assistance related to every element of the underlying
offense”). And so forth and so on.
                     Cite as: 572 U. S. ____ (2014)                    9

                          Opinion of the Court

would free neither party from liability.6
   Under that established approach, Rosemond’s participa-
tion in the drug deal here satisfies the affirmative-act
requirement for aiding and abetting a §924(c) violation.
As we have previously described, the commission of a drug
trafficking (or violent) crime is—no less than the use of a
firearm—an “essential conduct element of the §924(c)
offense.” United States v. Rodriguez-Moreno, 526 U. S.
275, 280 (1999); see supra, at 6. In enacting the statute,
“Congress proscribed both the use of the firearm and the
commission of acts that constitute” a drug trafficking
crime. Rodriguez-Moreno, 526 U. S, at 281. Rosemond
therefore could assist in §924(c)’s violation by facilitating
either the drug transaction or the firearm use (or of course
both). In helping to bring about one part of the offense
(whether trafficking drugs or using a gun), he necessarily
helped to complete the whole. And that ends the analysis
as to his conduct. It is inconsequential, as courts applying
both the common law and §2 have held, that his acts did
not advance each element of the offense; all that matters
is that they facilitated one component.
   Rosemond argues, to the contrary, that the requisite act
here “must be directed at the use of the firearm,” because
that element is §924(c)’s most essential feature. Brief for
Petitioner 33 (arguing that “it is the firearm crime” he was
really charged with aiding and abetting, “not the drug
trafficking crime”). But Rosemond can provide no author-
——————
   6 Consider a hypothetical similar to Johnson and Pereira (and a mod-

ern variant of the Wharton treatise’s, see n. 4, supra). Suppose that as
part of a kidnapping scheme, one accomplice lures the victim into a car
under false pretenses; another drives the vehicle; a third allows the use
of her house to hold the victim captive; and still a fourth keeps watch
outside to divert potential witnesses. None would have personally
completed, or even assisted with, all elements of the offense. See, e.g.,
United States v. Cervantes-Blanco, 504 F. 3d 576, 580 (CA5 2007)
(listing elements). But (if they had the requisite intent) all would be
liable under §2.
10             ROSEMOND v. UNITED STATES

                     Opinion of the Court

ity for demanding that an affirmative act go toward an
element considered peculiarly significant; rather, as just
noted, courts have never thought relevant the importance
of the aid rendered. See supra, at 7–8. And in any event,
we reject Rosemond’s premise that §924(c) is somehow
more about using guns than selling narcotics. It is true
enough, as Rosemond says in support of that theory, that
§924(c) “establishes a separate, freestanding offense that
is ‘distinct from the underlying [drug trafficking crime].’ ”
Brief for Petitioner 32 (quoting Simpson v. United States,
435 U. S. 6, 10 (1978)). But it is just as true that §924(c)
establishes a freestanding offense distinct from any that
might apply just to using a gun—say, for discharging a
firearm in a public park. That is because §924(c) is, to
coin a term, a combination crime. It punishes the tem-
poral and relational conjunction of two separate acts, on
the ground that together they pose an extreme risk of
harm. See Muscarello v. United States, 524 U. S. 125, 132
(1998) (noting that §924(c)’s “basic purpose” was “to com-
bat the dangerous combination of drugs and guns”). And
so, an act relating to drugs, just as much as an act relating
to guns, facilitates a §924(c) violation.
   Rosemond’s related argument that our approach would
conflate two distinct offenses—allowing a conviction for
abetting a §924(c) violation whenever the prosecution
shows that the defendant abetted the underlying drug
trafficking crime—fares no better. See Brief for Petitioner
38. That is because, as we will describe, an aiding and
abetting conviction requires not just an act facilitating one
or another element, but also a state of mind extending to
the entire crime. See infra, at 11. And under that rule, a
defendant may be convicted of abetting a §924(c) violation
only if his intent reaches beyond a simple drug sale, to an
armed one. Aiding and abetting law’s intent component—
to which we now turn—thus preserves the distinction
between assisting the predicate drug trafficking crime and
                     Cite as: 572 U. S. ____ (2014)                   11

                          Opinion of the Court

assisting the broader §924(c) offense.
                               B
  Begin with (or return to) some basics about aiding and
abetting law’s intent requirement, which no party here
disputes. As previously explained, a person aids and abets
a crime when (in addition to taking the requisite act) he
intends to facilitate that offense’s commission. See supra,
at 5–6. An intent to advance some different or lesser
offense is not, or at least not usually, sufficient: Instead,
the intent must go to the specific and entire crime
charged—so here, to the full scope (predicate crime plus
gun use) of §924(c). See, e.g., 2 LaFave §13.2(c); W. Clark
& W. Marshall, Law of Crimes, §187, pp. 251–253 (2d ed.
1905); ALI, Model Penal Code §2.06 Comment, p. 306
(1985).7 And the canonical formulation of that needed
state of mind—later appropriated by this Court and oft-
quoted in both parties’ briefs—is Judge Learned Hand’s:
To aid and abet a crime, a defendant must not just “in
some sort associate himself with the venture,” but also
“participate in it as in something that he wishes to bring
about” and “seek by his action to make it succeed.” Nye &
Nissen v. United States, 336 U. S. 613, 619 (1949) (quoting
Peoni, 100 F. 2d, at 402; see Brief for Petitioner 20, 28, 41;
Brief for United States 14, 51.
  We have previously found that intent requirement
satisfied when a person actively participates in a criminal
venture with full knowledge of the circumstances consti-
——————
   7 Some authorities suggest an exception to the general rule when

another crime is the “natural and probable consequence” of the crime
the defendant intended to abet. See, e.g., 2 LaFave §13.3(b), at 356
(citing cases); but see id., §13.3 (“Under the better view, one is not an
accomplice to a crime merely because . . . that crime was a natural and
probable consequence of another offense as to which he is an accom-
plice”). That question is not implicated here, because no one contends
that a §924(c) violation is a natural and probable consequence of simple
drug trafficking. We therefore express no view on the issue.
12                ROSEMOND v. UNITED STATES

                         Opinion of the Court

tuting the charged offense. In Pereira, the mail fraud case
discussed above, we found the requisite intent for aiding
and abetting because the defendant took part in a fraud
“know[ing]” that his confederate would take care of the
mailing. 347 U. S., at 12; see supra, at 8. Likewise, in
Bozza v. United States, 330 U. S. 160, 165 (1947), we up-
held a conviction for aiding and abetting the evasion of
liquor taxes because the defendant helped operate a clan-
destine distillery “know[ing]” the business was set up “to
violate Government revenue laws.” And several Courts of
Appeals have similarly held—addressing a fact pattern
much like this one—that the unarmed driver of a getaway
car had the requisite intent to aid and abet armed bank
robbery if he “knew” that his confederates would use
weapons in carrying out the crime. See, e.g., United States
v. Akiti, 701 F. 3d 883, 887 (CA8 2012); United States v.
Easter, 66 F. 3d 1018, 1024 (CA9 1995). So for purposes of
aiding and abetting law, a person who actively partici-
pates in a criminal scheme knowing its extent and charac-
ter intends that scheme’s commission.8
   The same principle holds here: An active participant in
a drug transaction has the intent needed to aid and abet a
§924(c) violation when he knows that one of his confeder-
ates will carry a gun. In such a case, the accomplice has
decided to join in the criminal venture, and share in its
benefits, with full awareness of its scope—that the plan
calls not just for a drug sale, but for an armed one. In so
doing, he has chosen (like the abettors in Pereira and
Bozza or the driver in an armed robbery) to align himself
——————
   8 We did not deal in these cases, nor do we here, with defendants who

incidentally facilitate a criminal venture rather than actively partici-
pate in it. A hypothetical case is the owner of a gun store who sells a
firearm to a criminal, knowing but not caring how the gun will be used.
We express no view about what sort of facts, if any, would suffice to
show that such a third party has the intent necessary to be convicted of
aiding and abetting.
                     Cite as: 572 U. S. ____ (2014)                   13

                          Opinion of the Court

with the illegal scheme in its entirety—including its use of
a firearm. And he has determined (again like those other
abettors) to do what he can to “make [that scheme] suc-
ceed.” Nye & Nissen, 336 U. S., at 619. He thus becomes
responsible, in the typical way of aiders and abettors, for
the conduct of others. He may not have brought the gun
to the drug deal himself, but because he took part in that
deal knowing a confederate would do so, he intended the
commission of a §924(c) offense—i.e., an armed drug sale.
  For all that to be true, though, the §924(c) defendant’s
knowledge of a firearm must be advance knowledge—or
otherwise said, knowledge that enables him to make the
relevant legal (and indeed, moral) choice. When an ac-
complice knows beforehand of a confederate’s design to
carry a gun, he can attempt to alter that plan or, if unsuc-
cessful, withdraw from the enterprise; it is deciding in-
stead to go ahead with his role in the venture that shows
his intent to aid an armed offense. But when an accom-
plice knows nothing of a gun until it appears at the scene,
he may already have completed his acts of assistance; or
even if not, he may at that late point have no realistic
opportunity to quit the crime. And when that is so, the
defendant has not shown the requisite intent to assist a
crime involving a gun. As even the Government concedes,
an unarmed accomplice cannot aid and abet a §924(c)
violation unless he has “foreknowledge that his confeder-
ate will commit the offense with a firearm.” Brief for
United States 38; see also infra, at 15–17. For the reasons
just given, we think that means knowledge at a time the
accomplice can do something with it—most notably, opt to
walk away.9
——————
  9 Of course, if a defendant continues to participate in a crime after a

gun was displayed or used by a confederate, the jury can permissibly
infer from his failure to object or withdraw that he had such knowledge.
In any criminal case, after all, the factfinder can draw inferences about
a defendant’s intent based on all the facts and circumstances of a
14               ROSEMOND v. UNITED STATES

                      Opinion of the Court

   Both parties here find something to dislike in our view
of this issue. Rosemond argues that a participant in a
drug deal intends to assist a §924(c) violation only if he
affirmatively desires one of his confederates to use a gun.
See Reply Brief 8–11. The jury, Rosemond concedes, could
infer that state of mind from the defendant’s advance
knowledge that the plan included a firearm. See Tr. of
Oral Arg. 5. But according to Rosemond, the instructions
must also permit the jury to draw the opposite conclusion—
that although the defendant participated in a drug
deal knowing a gun would be involved, he did not spe-
cifically want its carriage or use. That higher standard,
Rosemond claims, is necessary to avoid subjecting persons
of different culpability to the same punishment. Rose-
mond offers as an example an unarmed driver assisting in
the heist of a store: If that person spent the drive “trying
to persuade [his confederate] to leave [the] gun behind,”
then he should be convicted of abetting shoplifting, but not
armed robbery. Reply Brief 9.
   We think not. What matters for purposes of gauging
intent, and so what jury instructions should convey, is
that the defendant has chosen, with full knowledge, to
participate in the illegal scheme—not that, if all had been
left to him, he would have planned the identical crime.
Consider a variant of Rosemond’s example: The driver of a
getaway car wants to help rob a convenience store (and
argues passionately for that plan), but eventually accedes
when his confederates decide instead to hold up a national
bank. Whatever his original misgivings, he has the requi-
site intent to aid and abet bank robbery; after all, he put
aside those doubts and knowingly took part in that more
dangerous crime. The same is true of an accomplice who
knowingly joins in an armed drug transaction—regardless
whether he was formerly indifferent or even resistant to
——————
crime’s commission.
                 Cite as: 572 U. S. ____ (2014)          15

                     Opinion of the Court

using firearms. The law does not, nor should it, care
whether he participates with a happy heart or a sense of
foreboding. Either way, he has the same culpability,
because either way he has knowingly elected to aid in the
commission of a peculiarly risky form of offense.
  A final, metaphorical way of making the point: By virtue
of §924(c), using a firearm at a drug deal ups the ante. A
would-be accomplice might decide to play at those perilous
stakes. Or he might grasp that the better course is to fold
his hand. What he should not expect is the capacity to
hedge his bets, joining in a dangerous criminal scheme but
evading its penalties by leaving use of the gun to someone
else. Aiding and abetting law prevents that outcome, so
long as the player knew the heightened stakes when he
decided to stay in the game.
  The Government, for its part, thinks we take too strict a
view of when a defendant charged with abetting a §924(c)
violation must acquire that knowledge. As noted above,
the Government recognizes that the accused accomplice
must have “foreknowledge” of a gun’s presence. Brief for
United States 38; see supra, at 13. But the Government
views that standard as met whenever the accomplice,
having learned of the firearm, continues any act of assist-
ing the drug transaction. See Brief for United States 48.
According to the Government, the jury should convict such
a defendant even if he became aware of the gun only after
he realistically could have opted out of the crime.
  But that approach, we think, would diminish too far the
requirement that a defendant in a §924(c) prosecution
must intend to further an armed drug deal. Assume,
for example, that an accomplice agrees to participate in a
drug sale on the express condition that no one brings a
gun to the place of exchange. But just as the parties are
making the trade, the accomplice notices that one of his
confederates has a (poorly) concealed firearm in his jacket.
The Government would convict the accomplice of aiding
16                 ROSEMOND v. UNITED STATES

                          Opinion of the Court

and abetting a §924(c) offense if he assists in completing
the deal without incident, rather than running away or
otherwise aborting the sale. See Tr. of Oral Arg. 40. But
behaving as the Government suggests might increase the
risk of gun violence—to the accomplice himself, other
participants, or bystanders; and conversely, finishing the
sale might be the best or only way to avoid that danger.
In such a circumstance, a jury is entitled to find that the
defendant intended only a drug sale—that he never in-
tended to facilitate, and so does not bear responsibility for,
a drug deal carried out with a gun. A defendant manifests
that greater intent, and incurs the greater liability of
§924(c), when he chooses to participate in a drug transac-
tion knowing it will involve a firearm; but he makes no
such choice when that knowledge comes too late for him to
be reasonably able to act upon it.10
                             III
     Under these principles, the District Court erred in
——————
   10 Contrary to the dissent’s view, see post, at 3–4, nothing in this

holding changes the way the defenses of duress and necessity operate.
Neither does our decision remotely deny that the “intent to undertake
some act is . . . perfectly consistent with the motive of avoiding adverse
consequences which would otherwise occur.” Post, at 5. Our holding is
grounded in the distinctive intent standard for aiding and abetting
someone else’s act—in the words of Judge Hand, that a defendant must
not just “in some sort associate himself with the venture” (as seems to
be good enough for the dissent), but also “participate in it as in some-
thing that he wishes to bring about” and “seek by his action to make it
succeed.” Nye & Nissen v. United States, 336 U. S. 613, 619 (1949)
(quoting Peoni, 100 F. 2d, at 402). For the reasons just given, see
supra, at 13, 15–16, we think that intent standard cannot be satisfied if
a defendant charged with aiding and abetting a §924(c) offense learns
of a gun only after he can realistically walk away—i.e., when he has no
opportunity to decide whether “he wishes to bring about” (or make
succeed) an armed drug transaction, rather than a simple drug crime.
And because a defendant’s prior knowledge is part of the intent re-
quired to aid and abet a §924(c) offense, the burden to prove it resides
with the Government.
                 Cite as: 572 U. S. ____ (2014)           17

                     Opinion of the Court

instructing the jury, because it did not explain that Rose-
mond needed advance knowledge of a firearm’s presence.
Recall that the court stated that Rosemond was guilty of
aiding and abetting if “(1) [he] knew his cohort used a
firearm in the drug trafficking crime, and (2) [he] know-
ingly and actively participated in the drug trafficking
crime.” App. 196. We agree with that instruction’s second
half: As we have explained, active participation in a drug
sale is sufficient for §924(c) liability (even if the conduct
does not extend to the firearm), so long as the defendant
had prior knowledge of the gun’s involvement. See supra,
at 9, 11–13. The problem with the court’s instruction
came in its description of that knowledge requirement. In
telling the jury to consider merely whether Rosemond
“knew his cohort used a firearm,” the court did not direct
the jury to determine when Rosemond obtained the requi-
site knowledge. So, for example, the jury could have
convicted even if Rosemond first learned of the gun when
it was fired and he took no further action to advance the
crime. For that reason, the Government itself describes
the instruction’s first half as “potentially misleading,”
candidly explaining that “it would have been clearer to
say” that Rosemond had to know that his confederate
“ ‘ would use’ [a firearm] or something . . . that makes
absolutely clear that you [need] foreknowledge.” Tr. of
Oral Arg. 48–49. We agree with that view, and then some:
The court’s statement failed to convey that Rosemond had
to have advance knowledge, of the kind we have described,
that a confederate would be armed. See supra, at 13,
15–16.
    The Government contends that this problematic instruc-
tion looks more accurate when viewed in context. In
particular, the Government points to the District Court’s
prefatory “umbrella instruction” that to aid or abet a
crime, a defendant must “willfully and knowingly seek[ ]
by some act to help make the crime succeed.” App. 196;
18             ROSEMOND v. UNITED STATES

                     Opinion of the Court

Brief for United States 49. That statement, the Govern-
ment rightly notes, “mirrors” Judge Hand’s classic formu-
lation. Tr. of Oral Arg. 33; see supra, at 11. But the
statement is also pitched at a high level of generality.
Immediately afterward, the District Court provided the
jury with the two-pronged test noted above—thus indicat-
ing how the broad principle should apply to the specific
charge of abetting a §924(c) offense. We therefore do not
see how the “umbrella” statement could have cured the
court’s error. Indeed, a different contextual feature of the
case would only have amplified that mistake. As earlier
described, the prosecutor asserted in closing argument
that the court’s test was easily satisfied because “a person
cannot be present and active at a drug deal when shots are
fired and not know their cohort is using a gun.” App. 158;
see supra, at 3–4. The prosecutor thus invited the jury to
convict Rosemond even if he first learned of the gun as
it was discharged, and no matter what he did afterward.
Once again, then, the message to the jury was that it need
not find advance knowledge—exactly what we (and for
that matter the Government) have said is required.
   We send this case back to the Tenth Circuit to consider
the appropriate consequence, if any, of the District Court’s
error. The Government makes two arguments relevant to
that inquiry. First, it contends that Rosemond failed to
object specifically to the part of the trial court’s instruc-
tions we have found wanting; thus, the Government as-
serts, a plain-error standard should apply to his claim.
See Fed. Rule Crim. Proc. 52(b); Johnson v. United States,
520 U. S. 461, 465–467 (1997). Second, the Government
argues that any error in the court’s aiding and abetting
instruction was harmless, because the jury must have
found (based on another part of its verdict, not discussed
here) that Rosemond himself fired the gun. Those claims
were not raised or addressed below, and we see no special
reason to decide them in the first instance. See Travelers
                 Cite as: 572 U. S. ____ (2014)           19

                     Opinion of the Court

Casualty & Surety Co. of America v. Pacific Gas & Elec.
Co., 549 U. S. 443, 455 (2007). Accordingly, we vacate the
judgment below and remand the case for further proceed-
ings consistent with this opinion.
                                           It is so ordered.
                      Cite as: 572 U. S. ____ (2014)                      1

                           Opinion of ALITO, J.

SUPREME COURT OF THE UNITED STATES
                               _________________

                                No. 12–895
                               _________________


          JUSTUS C. ROSEMOND, PETITIONER v.

                    UNITED STATES

 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF 

            APPEALS FOR THE TENTH CIRCUIT

                             [March 5, 2014] 


   JUSTICE ALITO, with whom JUSTICE THOMAS joins, con-
curring in part and dissenting in part.
   I largely agree with the analysis in the first 12 pages of
the opinion of the Court, but I strongly disagree with
the discussion that comes after that point. Specifically, I
reject the Court’s conclusion that a conviction for aiding
and abetting a violation of 18 U. S. C. §924(c) demands
proof that the alleged aider and abettor had what the
Court terms “a realistic opportunity” to refrain from en­
gaging in the conduct at issue.1 Ante, at 13. This rule
represents an important and, as far as I am aware, un­
precedented alteration of the law of aiding and abetting
and of the law of intentionality generally.
   To explain my disagreement with the Court’s analysis, I
begin with our case law on the mens rea required to estab­
lish aiding and abetting. There is some tension in our
——————
   1 I am also concerned that the Court’s use, without clarification, of the

phrase “advance knowledge” will lead readers astray. E.g., ante, at 1.
Viewed by itself, the phrase most naturally means knowledge acquired
in advance of the commission of the drug trafficking offense, but this
is not what the Court means. Rather, “advance knowledge,” as used by
the Court, may include knowledge acquired while the drug trafficking
offense is in progress. Specifically, a defendant has such knowledge,
the Court says, if he or she first learns of the gun while the drug offense
is in progress and at that time “realistically could have opted out of the
crime.” Ante, at 15.
2              ROSEMOND v. UNITED STATES

                      Opinion of ALITO, J.

cases on this point. Specifically, some of our cases suggest
that an aider and abettor must act purposefully or with
intent. Prominent among these cases is Nye & Nissen v.
United States, 336 U. S. 613 (1949), which the Court
quotes. See ante, at 16, n. 10. In that case, the Court,
quoting Judge Learned Hand’s formulation in United
States v. Peoni, 100 F. 2d 401 (CA2 1938), said that an
aider and abettor must “ ‘participate in [the crime] as in
something that he wishes to bring about, [and] seek by his
action to make it succeed.’ ” 336 U. S., at 619.
   On the other hand, there are cases to which the Court
also refers, ante, at 12, that appear to hold that the requi­
site mens rea is simply knowledge. See Pereira v. United
States, 347 U. S. 1, 12 (1954); Bozza v. United States, 330
U. S. 160, 164–165 (1947). The Court refers interchange­
ably to both of these tests and thus leaves our case law in
the same, somewhat conflicted state that previously ex-
isted. But because the difference between acting purpose­
fully (when that concept is properly understood) and acting
knowingly is slight, this is not a matter of great concern.
   Beginning on page 13, however, the Court veers off in a
new and, to my mind, most unfortunate direction. The
Court imagines the following situation:
     “[A]n accomplice agrees to participate in a drug sale
     on the express condition that no one brings a gun to
     the place of exchange. But just as the parties are
     making the trade, the accomplice notices that one of
     his confederates has a (poorly) concealed firearm in
     his jacket.” Ante, at 15.
If the accomplice, despite spotting the gun, continues to
assist in the completion of the drug sale, has the accom­
plice aided and abetted the commission of a violation of
§924(c)?
   The Court’s answer is “it depends.” Walking away, the
Court observes, “might increase the risk of gun violence—
to the accomplice himself, other participants, or bystand­
                     Cite as: 572 U. S. ____ (2014)                     3

                          Opinion of ALITO, J.

ers; and conversely, finishing the sale might be the best or
only way to avoid the danger.” Ante, at 16. Moreover—
and this is where the seriously misguided step occurs—the
Court says that if the risk of walking away exceeds (by
some unspecified degree) the risk created by completing
the sale and if the alleged aider and abettor chooses to
continue for that reason, the alleged aider and abettor
lacks the mens rea required for conviction. See ante, at 16,
n. 10.
   What the Court has done is to convert what has up to
now been an affirmative defense into a part of the re­
quired mens rea, and this step has very important concep­
tual and practical consequences. It fundamentally alters
the prior understanding of mental states that form the
foundation of substantive criminal law, and it places a
strange and difficult burden on the prosecution.
   That the Court has taken a radical step can be seen by
comparing what the Court now holds with the traditional
defense of necessity. That defense excuses a violation of
law if “the harm which will result from compliance with
the law is greater than that which will result from viola­
tion of it.” 2 W. LaFave, Substantive Criminal Law §10.1,
p. 116 (2003) (hereinafter LaFave).2 This is almost exactly
the balance-of-risks calculus adopted by the Court, but
under the traditional approach necessity is an affirmative
defense. See, e.g., United States v. Bailey, 444 U. S. 394,
416 (1980). Necessity and the closely related defense of
duress are affirmative defenses because they almost invar­
——————
  2 Traditionally, the defense of necessity was employed when natural
forces created the situation justifying non-compliance; when the situa­
tion was the product of human action, duress was the appropriate
defense. 2 LaFave §10.1(a), at 116. But “[m]odern cases have tended to
blur the distinction between” these two defenses, United States v.
Bailey, 444 U. S. 394, 410 (1980), and “it would doubtless be possible to
treat [duress] as a branch of the law of necessity,” 2 LaFave §10.1(b), at
121.
4               ROSEMOND v. UNITED STATES

                      Opinion of ALITO, J.

iably do not negate the mens rea necessary to incur crimi­
nal liability. See 2 LaFave §10.1(a), at 118 (“The rationale
of the necessity defense is not that a person, when faced
with the pressure of circumstances of nature, lacks the
mental element which the crime in question requires”);
id., §9.7(a), at 73 (same for duress).
    This Court has made clear that, except in narrow cir­
cumstances, necessity and duress do not negate the mens
rea required for conviction. In Dixon v. United States, 548
U. S. 1 (2006), the defendant was charged with “know-
ingly” and “willfully” committing certain criminal acts, but
she claimed that she committed the acts only because her
boyfriend had threatened to kill her or hurt her daughters
if she did not do so. Id., at 4. She contended that she
could not “have formed the necessary mens rea for these
crimes because she did not freely choose to commit the
acts in question,” but we rejected that argument, explain­
ing that “[t]he duress defense, like the defense of necessity
. . . , may excuse conduct that would otherwise be punish­
able, but the existence of duress normally does not contro­
vert any of the elements of the offense itself.” Id., at 6. In
a footnote, we suggested one situation in which the prose­
cution might be required to disprove duress, namely,
where a particular crime demands proof that the accused
acted “maliciously,” which is to say “without justification
or excuse.” Ibid., n. 4 (internal quotation marks omitted).
    The Court justifies its holding on the ground that the
mens rea standard articulated in Nye & Nissen also falls
within an exception to the general rule that proof of neces­
sity or duress does not negate mens rea. Ante, at 16, n. 10.
But the Court, having refrained on pages 11–12 of its
opinion from deciding whether aiding and abetting re­
quires purposeful, as opposed to knowing, conduct, quickly
and without explanation jettisons the “knowing” standard
and concludes that purposeful conduct is needed. This is a
critical move because if it is enough for an alleged aider
                 Cite as: 572 U. S. ____ (2014)            5

                      Opinion of ALITO, J.

and abettor simply to know that his confederate is carry­
ing a gun, then the alleged aider and abettor in the
Court’s hypothetical case (who spots the gun on the con­
federate’s person) unquestionably had the mens rea needed
for conviction.
  But even accepting the Nye & Nissen standard as the
exclusive means of proving the required mens rea, the
Court’s analysis is still quite wrong. Under the Nye &
Nissen standard, the Government must simply prove that
a defendant had as his conscious object that the hypothet­
ical drug sale (which, as the defendant knew, included the
carrying of a gun by one of the participants) go forward to
completion. See Nye & Nissen, 336 U. S., at 619. Such
intent is perfectly consistent with facts supporting a ne­
cessity or duress defense. A person can certainly intend
the success of a criminal enterprise that he aids on the
belief that doing so will give rise to a lesser evil than his
refusal to participate would bring about.
  The Court confuses two fundamentally distinct concepts:
intent and motive. It seems to assume that, if a defend­
ant’s motive in aiding a criminal venture is to avoid some
greater evil, he does not have the intent that the venture
succeed. But the intent to undertake some act is of course
perfectly consistent with the motive of avoiding adverse
consequences which would otherwise occur. We can all
testify to this from our daily experience. People wake up,
go to work, balance their checkbooks, shop for groceries—
and yes, commit crimes—because they believe something
bad will happen if they do not do these things, not because
the deepest desire of their heart is to do them. A person
may only go to work in the morning to keep his or her
family from destitution; that does not mean he or she does
not intend to put in a full day’s work. In the same way,
the fact that a defendant carries out a crime because he
feels he must do so on pain of terrible consequences does
not mean he does not intend to carry out the crime. When
6               ROSEMOND v. UNITED STATES

                       Opinion of ALITO, J.

Jean Valjean stole a loaf of bread to feed his starving
family, he certainly intended to commit theft; the fact
that, had he been living in America today, he may have
pleaded necessity as a defense does not change that fact.
See V. Hugo, Les Misérables 54 (Fall River Press ed.
2012).
    Common-law commentators recognized this elementary
distinction between intent and motive. As Sir James
FitzJames Stephen explains, if “A puts a loaded pistol to
B’s temple and shoots B through the head deliberately,
. . . . [i]t is obvious that in every such case the intention of
A must be to kill B.” 2 A History of the Criminal Law of
England 110–111 (1883). This fact “throws no light what­
ever on A’s motives for killing B. They may have been
infinitely various. . . . The motive may have been a desire
for revenge, or a desire for plunder, or a wish on A’s part
to defend himself against an attack by B, . . . or to put a
man already mortally wounded out of his agony.” Id., at
111. “In all these cases the intention is the same, but the
motives are different, and in all the intention may remain
unchanged from first to last whilst the motives may vary
from moment to moment.” Ibid.
    Unsurprisingly, our cases have recognized that a lawful
motive (such as necessity, duress, or self-defense) is con­
sistent with the mens rea necessary to satisfy a require­
ment of intent. In Martin v. Ohio, 480 U. S. 228 (1987),
we considered whether due process permitted the State of
Ohio to place the burden of proving self-defense on a de­
fendant charged with aggravated murder. Under the Ohio
statute, aggravated murder consisted of “purposely, and
with prior calculation and design, caus[ing] the death of
another.” Id., at 230 (alteration in original; internal quo­
tation marks omitted). Martin pleaded self-defense, which
required her to prove that (1) she was “not at fault in
creating the situation giving rise to the argument” with
the victim, (2) she “had an honest belief that she was in
                 Cite as: 572 U. S. ____ (2014)            7

                      Opinion of ALITO, J.

imminent danger of death or great bodily harm, and that
her only means of escape from such danger was in the use
of . . . force,” and (3) she “did not violate any duty to re­
treat or avoid danger.” Ibid. Martin argued that due
process did not permit the State to impose the burden of
proving self-defense on her, because proving self-defense
would necessarily negate the elements of aggravated
murder, which the State was required to prove beyond a
reasonable doubt. We disagreed, explaining that the
elements which the State was required to prove to convict
Martin were not the same as the elements which Martin
was required to prove to prevail on her self-defense theory.
Id., at 233. By so holding, we recognized that a defend­
ant’s purpose to kill another is not incompatible with that
defendant’s “honest belief that she was in imminent dan­
ger of death or great bodily harm” and that her use of force
was necessary to preserve her life. Id., at 230. In other
words, the fact that a defendant intends to kill another
only to avert mortal peril does not mean that the defend­
ant does not intend to kill.
  That principle plays out in a wide variety of cases.
United States v. Leal-Cruz, 431 F. 3d 667 (CA9 2005),
provides a good example. There, the Ninth Circuit had
to decide whether a defendant could constitutionally be
required to bear the burden of proving duress as a defense
to conviction under 8 U. S. C. §1326 for attempted illegal
reentry into the United States. Leal-Cruz pleaded duress,
testifying that he entered the United States only to escape
the deadly threat posed by abusive Mexican police officers
who were chasing him. 431 F. 3d, at 669. The Ninth
Circuit had earlier held that the mens rea required for
conviction for attempted illegal reentry was “purpose, i.e.,
conscious desire, to reenter the United States.” Id., at
671. The Court of Appeals nevertheless found that the
Constitution permitted imposition of the burden of proving
duress on Leal-Cruz, because proving duress did not re­
8               ROSEMOND v. UNITED STATES

                      Opinion of ALITO, J.

quire him to prove that he had not purposely entered the
United States. As the Ninth Circuit explained, duress and
the mens rea requirement of intent did not overlap be­
cause Leal-Cruz “had the ‘conscious desire’ to enter the
country, even if the act of crossing the border was done to
escape harm.” Id., at 673.
   Thus, it seems inarguable to me that the existence of
the purpose or intent to carry out a crime is perfectly
compatible with facts giving rise to a necessity or duress
defense. Once that proposition is established, the Court’s
error is readily apparent. The Court requires the Gov­
ernment to prove that a defendant in Rosemond’s situa­
tion could have walked away without risking harm greater
than he would cause by continuing with the crime—
circumstances that traditionally would support a necessity
or duress defense. It imposes this requirement on the
Government despite the fact that such dangerous circum­
stances simply do not bear on whether the defendant
intends the §924(c) offense to succeed, as (on the Court’s
reading) is required for aiding and abetting liability.
   The usual rule that a defendant bears the burden of
proving affirmative defenses is justified by a compelling,
commonsense intuition: “[W]here the facts with regard to
an issue lie peculiarly in the knowledge of a party, that
party is best situated to bear the burden of proof.” Smith
v. United States, 568 U. S. ___, ___ (2013) (slip op., at 6–7)
(quoting Dixon, 548 U. S., at 9; alteration in original
and internal quotation marks omitted). By abandoning
that rule in cases involving aiding and abetting of §924(c)
offenses, the Court creates a perverse arrangement
whereby the prosecution must prove something that is
peculiarly within the knowledge of the defendant. Imag­
ine that A aids B in committing a §924(c) offense and
claims that he only learned of the gun once the crime had
begun. If A had the burden of proof, he might testify that
B was a hothead who had previously shot others who had
                  Cite as: 572 U. S. ____ (2014)            9

                       Opinion of ALITO, J.

crossed him. But under the Court’s rule, the prosecution,
in order to show the intent needed to convict A as an aider
and abettor, presumably has the burden of proving that B
was not such a person and that A did not believe him to
be. How is the prosecution to do this? By offering testi­
mony by B’s friends and associates regarding his peaceful
and easygoing nature? By introducing entries from A’s
diary in which he reflects on the sense of safety he feels
when carrying out criminal enterprises in B’s company?
Furthermore, even if B were a hothead and A knew him to
be such, A would presumably only be entitled to escape
liability if he continued with the offense because of his fear
of B’s reaction if he walked away. Under the Court’s rule,
it is up to the Government to prove that A’s continued
participation was not on account of his fear of B—but how?
By introducing footage of a convenient security camera
demonstrating that A’s eyes were not wide with fear, nor
his breathing rapid?
   The Court’s rule breaks with the common-law tradition
and our case law. It also makes no sense. I respectfully
dissent from that portion of the Court’s opinion which
places on the Government the burden of proving that the
alleged aider and abettor of a §924(c) offense had what the
Court terms “a realistic opportunity” to refrain from en­
gaging in the conduct at issue.
