(Slip Opinion)              OCTOBER TERM, 2005                                       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

                      DIXON v. UNITED STATES

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

      No. 05–7053. Argued April 25, 2006—Decided June 22, 2006
Petitioner was charged with receiving a firearm while under indictment
  in violation of 18 U. S. C. §922(n) and with making false statements
  in connection with the acquisition of a firearm in violation of
  §922(a)(6). She admitted at trial that she knew she was under in
  dictment when she purchased the firearms and knew that doing so
  was a crime, but claimed that she was acting under duress because
  her boyfriend had threatened to harm her and her daughters if she
  did not buy the guns for him. Bound by Fifth Circuit precedent, the
  District Court declined her request for a jury instruction placing
  upon the Government the burden to disprove, beyond a reasonable
  doubt, her duress defense. Instead, the jury was instructed that peti
  tioner had the burden to establish her defense by a preponderance of
  the evidence. She was convicted, and the Fifth Circuit affirmed.
Held:
    1. The jury instructions did not run afoul of the Due Process
 Clause. The crimes of conviction require that petitioner have acted
 “knowingly,” §922(a)(6)—which “merely requires proof of knowledge
 of the facts that constitute the offense,” Bryan v. United States, 524
 U. S. 184, 193—or “willfully,” §924(a)(1)(D)—which requires acting
 “with knowledge that [the] conduct was unlawful,” ibid. Thus, the
 Government bore the burden of proving beyond a reasonable doubt
 that petitioner knew that she was making false statements and knew
 that she was breaking the law when she acquired a firearm while
 under indictment. It clearly met its burden when petitioner testified
 to that effect. Petitioner contends that she cannot have formed the
 necessary mens rea because she did not freely choose to commit the
 crimes. However, while the duress defense may excuse conduct that
 would otherwise be punishable, see United States v. Bailey, 444 U. S.
2                      DIXON v. UNITED STATES

                                 Syllabus

    394, 409–410, the existence of duress normally does not controvert
    any of the elements of the offense itself. The fact that petitioner’s
    crimes are statutory offenses with no counterpart in the common law
    supports this conclusion. The jury instructions were consistent with
    the requirement that the Government prove the mental states speci
    fied in §§922(a)(6) and 924(a)(1)(D) and did not run afoul of due proc
    ess by placing the burden on petitioner to establish duress by a pre
    ponderance of the evidence. Pp. 3–5.
       2. Modern common law does not require the Government to bear
    the burden of disproving petitioner’s duress defense beyond a reason
    able doubt. The long-established common-law rule, which places the
    burden of proving that defense on the defendant, was not upset by
    Davis v. United States, 160 U. S. 469. There, the Court interpreted a
    defendant’s insanity to controvert the necessary mens rea for a mur
    der committed “feloniously, wilfully, and of his malice aforethought,”
    id., at 474, and required the Government to prove the defendant’s
    sanity beyond a reasonable doubt because the evidence tending to
    prove insanity also tended to disprove an essential element of the of
    fense. The duress evidence that petitioner adduced at trial does not
    contradict or tend to disprove any element of her statutory offenses.
    She is also not helped by the resulting “Davis rule,” which was not
    constitutionally mandated, and which Congress overruled by statute,
    requiring a defendant to prove insanity by clear and convincing evi
    dence.
       Petitioner’s reliance on Davis also ignores the fact that federal
    crimes are “solely creatures of statute,” Liparota v. United States,
    471 U. S. 419, 424, and thus the Court must effectuate the duress de
    fense as Congress “may have contemplated” it in the context of these
    specific offenses, United States v. Oakland Cannabis Buyers’ Coop
    erative, 532 U. S. 483, 490, n. 3. The Court can assume that, when
    passing the relevant 1968 Act, Congress was familiar with the long-
    established common-law rule and the rule of McKelvey v. United
    States, 260 U. S. 353, 357—that the one relying on an affirmative de
    fense must set it up and establish it—and would have expected fed
    eral courts to apply a similar approach to any affirmative defense or
    excuse for violating the new law. To accept petitioner’s contrary hy
    pothesis that Davis dramatically upset well-settled law would require
    an overwhelming consensus among federal courts placing the burden
    on the Government, but conflict among the Circuits demonstrates
    that such consensus has never existed. For a similar reason, no
    weight is due the 1962 Model Penal Code. There is no evidence that
    Congress endorsed the Code’s views or incorporated them into the
    1968 Act. In fact, when Congress amended the Act to add a mens rea
    requirement, it punished “willful” violations, a mental state not em
                     Cite as: 548 U. S. ____ (2006)                    3

                                Syllabus

  braced by the Code. Effectuating the affirmative defense as Congress
  may have contemplated it, the Court presumes that, in the context of
  the firearms offenses here and the long-established common-law rule,
  Congress intended petitioner to bear the burden of proving the duress
  defense by a preponderance of the evidence. Pp. 5–15.
413 F. 3d 520, affirmed.

  STEVENS, J., delivered the opinion of the Court, in which ROBERTS,
C. J., and SCALIA, KENNEDY, THOMAS, GINSBURG, and ALITO, JJ., joined.
KENNEDY, J., filed a concurring opinion. ALITO, J., filed a concurring
opinion, in which SCALIA, J., joined. BREYER, J., filed a dissenting opin
ion, in which SOUTER, J., joined.
                        Cite as: 548 U. S. ____ (2006)                              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. 05–7053
                                   _________________


 KESHIA CHERIE ASHFORD DIXON, PETITIONER v.

               UNITED STATES

 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF

            APPEALS FOR THE FIFTH CIRCUIT

                                 [June 22, 2006] 


  JUSTICE STEVENS delivered the opinion of the Court.
  In January 2003, petitioner Keshia Dixon purchased
multiple firearms at two gun shows, during the course of
which she provided an incorrect address and falsely stated
that she was not under indictment for a felony. As a
result of these illegal acts, petitioner was indicted and
convicted on one count of receiving a firearm while under
indictment in violation of 18 U. S. C. §922(n) and eight
counts of making false statements in connection with the
acquisition of a firearm in violation of §922(a)(6). At trial,
petitioner admitted that she knew she was under indict
ment when she made the purchases and that she knew
doing so was a crime; her defense was that she acted
under duress because her boyfriend threatened to kill her
or hurt her daughters if she did not buy the guns for him.
  Petitioner contends that the trial judge’s instructions to
the jury erroneously required her to prove duress by a
preponderance of the evidence instead of requiring the
Government to prove beyond a reasonable doubt that she
did not act under duress. The Court of Appeals rejected
petitioner’s contention, 413 F. 3d 520 (CA5 2005); given
2                     DIXON v. UNITED STATES

                          Opinion of the Court

contrary treatment of the issue by other federal courts,1
we granted certiorari, 546 U. S. __ (2006).
                              I
  At trial, in her request for jury instructions on her
defense of duress, petitioner contended that she “should
have the burden of production, and then that the Govern
ment should be required to disprove beyond a reasonable
doubt the duress.” App. 300. Petitioner admitted that
this request was contrary to Fifth Circuit precedent, and
the trial court, correctly finding itself bound by Circuit
precedent, denied petitioner’s request. Ibid. Instead, the
judge’s instructions to the jury defined the elements of the
duress defense2 and stated that petitioner has “the burden
of proof to establish the defense of duress by a preponder
ance of the evidence.” Id., at 312.
  Petitioner argues here, as she did in the District Court
and the Court of Appeals, that federal law requires the
Government to bear the burden of disproving her defense
beyond a reasonable doubt and that the trial court’s erro

——————
    1 Cf.,
        e.g., United States v. Talbott, 78 F. 3d 1183, 1186 (CA7 1996)
(per curiam); United States v. Riffe, 28 F. 3d 565, 568, n. 2 (CA6 1994);
United States v. Simpson, 979 F. 2d 1282, 1287 (CA8 1992).
  2 There is no federal statute defining the elements of the duress de

fense. We have not specified the elements of the defense, see, e.g.,
United States v. Bailey, 444 U. S. 394, 409–410 (1980), and need not do
so today. Instead, we presume the accuracy of the District Court’s
description of these elements: (1) The defendant was under an unlawful
and imminent threat of such a nature as to induce a well-grounded
apprehension of death or serious bodily injury; (2) the defendant had
not recklessly or negligently placed herself in a situation in which it
was probable that she would be forced to perform the criminal conduct;
(3) the defendant had no reasonable, legal alternative to violating the
law, that is, a chance both to refuse to perform the criminal act and also
to avoid the threatened harm; and, (4) that a direct causal relationship
may be reasonably anticipated between the criminal act and the avoid
ance of the threatened harm. See App. 312–313; see generally United
States v. Harper, 802 F. 2d 115, 118 (CA5 1986).
                    Cite as: 548 U. S. ____ (2006)                  3

                        Opinion of the Court

neous instruction on this point entitles her to a new trial.
There are two aspects to petitioner’s argument in support
of her proposed instruction that merit separate discussion.
First, petitioner contends that her defense “controverted
the mens rea required for conviction” and therefore that
the Due Process Clause requires the Government to retain
the burden of persuasion on that element. Brief for Peti
tioner 41. Second, petitioner argues that Fifth Circuit’s
rule is “contrary to modern common law.” Id., at 14.
                              II
   The crimes for which petitioner was convicted require
that she have acted “knowingly,” §922(a)(6), or “willfully,”
§924(a)(1)(D).3 As we have explained, “unless the text of
the statute dictates a different result, the term ‘knowingly’
merely requires proof of knowledge of the facts that consti
tute the offense.” Bryan v. United States, 524 U. S. 184,
193 (1998) (footnote omitted). And the term “willfully” in
§924(a)(1)(D) requires a defendant to have “acted with
knowledge that his conduct was unlawful.” Ibid. In this
case, then, the Government bore the burden of proving
beyond a reasonable doubt that petitioner knew she was
making false statements in connection with the acquisi
tion of firearms and that she knew she was breaking the
law when she acquired a firearm while under indictment.
See In re Winship, 397 U. S. 358, 364 (1970). Although the
Government may have proved these elements in other
ways, it clearly met its burden when petitioner testified
that she knowingly committed certain acts—she put a
false address on the forms she completed to purchase the
firearms, falsely claimed that she was the actual buyer of
the firearms, and falsely stated that she was not under
indictment at the time of the purchase—and when she
——————
  3 Although §922(n) does not contain a mens rea requirement, the rele

vant sentencing provision, §924(a)(1)(D), requires that a violation be
committed willfully.
4                     DIXON v. UNITED STATES

                          Opinion of the Court

testified that she knew she was breaking the law when, as
an individual under indictment at the time, she purchased
a firearm. App. 221–222.
  Petitioner contends, however, that she cannot have
formed the necessary mens rea for these crimes because
she did not freely choose to commit the acts in question.
But even if we assume that petitioner’s will was overborne
by the threats made against her and her daughters, she
still knew that she was making false statements and knew
that she was breaking the law by buying a firearm. The
duress defense, like the defense of necessity that we con
sidered in United States v. Bailey, 444 U. S. 394, 409–410
(1980), may excuse conduct that would otherwise be pun
ishable, but the existence of duress normally does not
controvert any of the elements of the offense itself.4 As we
explained in Bailey, “[c]riminal liability is normally based
upon the concurrence of two factors, ‘an evil-meaning
mind [and] and evil-doing hand . . . .’ ” Id., at 402 (quoting
Morissette v. United States, 342 U. S. 246, 251 (1952)).
Like the defense of necessity, the defense of duress does
not negate a defendant’s criminal state of mind when the
applicable offense requires a defendant to have acted
knowingly or willfully; instead, it allows the defendant to
“avoid liability . . . because coercive conditions or necessity
negates a conclusion of guilt even though the necessary
mens rea was present.” Bailey, 444 U. S., at 402.5
——————
   4 As the Government recognized at oral argument, there may be

crimes where the nature of the mens rea would require the Government
to disprove the existence of duress beyond a reasonable doubt. See Tr.
of Oral Arg. 26–27; see also, e.g., 1 W. LaFave, Substantive Criminal
Law §5.1, p. 333 (2d ed. 2003) (hereinafter LaFave) (explaining that
some common-law crimes require that the crime be done “ ‘mali
ciously’ ”); Black’s Law Dictionary 968 (7th ed. 1999) (defining malice as
“[t]he intent, without justification or excuse, to commit a wrongful act”).
   5 Professor LaFave has explained the duress defense as follows:

   “The rationale of the defense is not that the defendant, faced with the
unnerving threat of harm unless he does an act which violates the
                     Cite as: 548 U. S. ____ (2006)                    5

                          Opinion of the Court

  The fact that petitioner’s crimes are statutory offenses
that have no counterpart in the common law also supports
our conclusion that her duress defense in no way disproves
an element of those crimes. We have observed that “[t]he
definition of the elements of a criminal offense is en
trusted to the legislature, particularly in the case of fed
eral crimes, which are solely creatures of statute.” Lipa
rota v. United States, 471 U. S. 419, 424 (1985). Here,
consistent with the movement away from the traditional
dichotomy of general versus specific intent and toward a
more specifically defined hierarchy of culpable mental
states, see Bailey, 444 U. S., at 403–404, Congress defined
the crimes at issue to punish defendants who act “know
ingly,” §922(a)(6), or “willfully,” §924(a)(1)(D). It is these
specific mental states, rather than some vague “evil mind,”
Brief for Petitioner 42, or “ ‘criminal’ intent,” Martin v.
Ohio, 480 U. S. 228, 235 (1987), that the Government is
required to prove beyond a reasonable doubt, see Patterson
v. New York, 432 U. S. 197, 211, n. 12 (1977) (“The appli
cability of the reasonable-doubt standard, however, has
always been dependent on how a State defines the offense
that is charged in any given case”). The jury instructions
in this case were consistent with this requirement and, as
such, did not run afoul of the Due Process Clause when
they placed the burden on petitioner to establish the
existence of duress by a preponderance of the evidence.
                         III
  Having found no constitutional basis for placing upon
the Government the burden of disproving petitioner’s
——————
literal language of the criminal law, somehow loses his mental capacity
to commit the crime in question. Nor is it that the defendant has not
engaged in a voluntary act. Rather it is that, even though he has done
the act the crime requires and has the mental state which the crime
requires, his conduct which violates the literal language of the criminal
law is excused . . . .” 2 LaFave §9.7(a), at 72 (footnote omitted).
6                 DIXON v. UNITED STATES

                      Opinion of the Court

duress defense beyond a reasonable doubt, we next ad
dress petitioner’s argument that the modern common law
requires the Government to bear that burden. In making
this argument, petitioner recognizes that, until the end of
the 19th century, common-law courts generally adhered to
the rule that “the proponent of an issue bears the burden
of persuasion on the factual premises for applying the
rule.” Fletcher, Two Kinds of Legal Rules: A Comparative
Study of Burden-of-Persuasion Practices in Criminal
Cases, 77 Yale L. J. 880, 898 (1967–1968). In petitioner’s
view, however, two important developments have estab
lished a contrary common-law rule that now prevails in
federal courts: this Court’s decision in Davis v. United
States, 160 U. S. 469 (1895), which placed the burden on
the Government to prove a defendant’s sanity, and the
publication of the Model Penal Code in 1962.
   Although undisputed in this case, it bears repeating
that, at common law, the burden of proving “affirmative
defenses—indeed, ‘all circumstances . . . of justification,
excuse or alleviation’—rested on the defendant.” Patter
son, 432 U. S., at 202 (quoting 4 W. Blackstone, Commen
taries *201); see also Martin v. Ohio, 480 U. S., at 235;
Mullaney v. Wilbur, 421 U. S. 684, 693 (1975). This com
mon-law rule accords with the general evidentiary rule
that “the burdens of producing evidence and of persuasion
with regard to any given issue are both generally allocated
to the same party.” 2 J. Strong, McCormick on Evidence
§337, p. 415 (5th ed. 1999). And, in the context of the
defense of duress, it accords with the doctrine that “where
the facts with regard to an issue lie peculiarly in the
knowledge of a party, that party has the burden of proving
the issue.” Id., at 413. Although she claims that the
common-law rule placing the burden on a defendant to
prove the existence of duress “was the product of flawed
reasoning,” petitioner accepts that this was the general
rule, at least until this Court’s decision in Davis. Brief for
                  Cite as: 548 U. S. ____ (2006)            7

                      Opinion of the Court

Petitioner 18. According to petitioner, however, Davis
initiated a revolution that overthrew the old common-law
rule and established her proposed rule in its place.
   Davis itself, however, does not support petitioner’s
position. In that case, we reviewed a defendant’s convic
tion for having committed murder “feloniously, wilfully,
and of his malice aforethought.” 160 U. S., at 474. It was
undisputed that the prosecution’s evidence “if alone con
sidered, made it the duty of the jury to return a verdict of
guilty of the crime charged”; the defendant, however,
adduced evidence at trial tending to show that he did not
have the mental capacity to form the requisite intent. Id.,
at 475. At issue before the Court was the correctness of
the trial judge’s instruction to the jury that the law “ ‘pre
sumes every man is sane, and the burden of showing it is
not true is upon the party who asserts it.’ ” Id., at 476.
Under this instruction, “if the evidence was in equilibrio
as to the accused being sane, that is, capable of compre
hending the nature and effect of his acts, he was to be
treated just as he would be if there were no defence of
insanity or if there was an entire absence of proof that he
was insane.” Id., at 479.
   In reversing the defendant’s conviction, we found our
selves “unable to assent to the doctrine that in a prosecu
tion for murder . . . it is the duty of the jury to convict
where the evidence is equally balanced on the issue as to
the sanity of the accused at the time of the killing.” Id., at
484 (emphasis added). Instead, we concluded that this
defendant was “entitled to an acquittal of the specific
crime charged if upon all the evidence there is reasonable
doubt whether he was capable in law of committing the
crime.” Ibid. (emphasis added). Our opinion focused on
the “definition of murder,” explaining that “it is of the very
essence of that heinous crime that it be committed by a
person of ‘sound memory and discretion,’ and with ‘malice
aforethought.’ ” Ibid. (citations omitted). Reviewing “the
8                DIXON v. UNITED STATES

                     Opinion of the Court

adjudged cases” and “elementary treatises upon criminal
law,” we found that “[a]ll admit that the crime of murder
necessarily involves the possession by the accused of such
mental capacity as will render him criminally responsible
for his acts.” Id., at 485. Thus, when we ultimately found
that the burden of proving the accused’s sanity rested on
the Government, our holding rested on the conclusion
that:
     “[Davis’] guilt cannot be said to have been proved be
    yond a reasonable doubt—his will and his acts cannot
    be held to have joined in perpetrating the murder
    charged—if the jury, upon all the evidence, have a
    reasonable doubt whether he was legally capable of
    committing crime, or (which is the same thing)
    whether he wilfully, deliberately, unlawfully, and of
    malice aforethought took the life of the deceased. As
    the crime of murder involves sufficient capacity to dis
    tinguish between right and wrong, the legal interpre
    tation of every verdict of guilty as charged is that the
    jury believed from all the evidence beyond a reason
    able doubt that the accused was guilty, and was there
    fore responsible, criminally, for his acts. How then
    upon principle or consistently with humanity can a
    verdict of guilty be properly returned, if the jury en
    tertain a reasonable doubt as to the existence of a fact
    which is essential to guilt, namely, the capacity in law
    of the accused to commit that crime?” Id., at 488.
   Our opinion in Davis, then, interpreted a defendant’s
sanity to controvert the necessary mens rea for the crime
of murder committed “feloniously, wilfully, and of his mal
ice aforethought,” id., at 474, as “[o]ne who takes human
life cannot be said to be actuated by malice aforethought,
or to have deliberately intended to take life, or to have ‘a
wicked, depraved, and malignant heart,’ . . . unless at the
                  Cite as: 548 U. S. ____ (2006)            9

                      Opinion of the Court

time he had sufficient mind to comprehend the criminality
or the right and wrong of such an act,” id., at 485. We
required the Government to prove the defendant’s sanity
beyond a reasonable doubt because the evidence that
tended to prove insanity also tended to disprove an essential
element of the offense charged. See Davis v. United States,
165 U. S. 373, 378 (1897) (“[T]he fact of sanity, as any
other essential fact in the case, must be established to the
satisfaction of the jury beyond a reasonable doubt” (em
phasis added)). Whether or not this reasoning correctly
treated insanity as negating the mens rea for murder as
defined in the statute at issue, cf., n. 4, supra, it does not
help petitioner: The evidence of duress she adduced at trial
does not contradict or tend to disprove any element of the
statutory offenses that she committed.
   Nor does the proposition for which Davis has come to
stand help petitioner’s cause. Although written more
narrowly in the context of a prosecution for the crime of
murder, Davis was later interpreted to establish a general
“rule for federal prosecutions . . . that an accused is ‘enti
tled to an acquittal of the specific crime charged if upon all
the evidence there is reasonable doubt whether he was
capable in law of committing crime.’ ” Leland v. Oregon,
343 U. S. 790, 797 (1952) (quoting Davis, 160 U. S., at
484); see also Lynch v. Overholser, 369 U. S. 705, 713
(1962) (explaining that the Davis rule applied in all fed
eral courts). After Davis, if a federal defendant introduced
sufficient evidence to raise a reasonable doubt as to his
sanity, it was sufficient to create a question for the jury on
which the Government bore the ultimate burden of per
suasion beyond a reasonable doubt. See, e.g., Hall v.
United States, 295 F. 2d 26, 28 (CA4 1961); Holloway v.
United States, 148 F. 2d 665, 666 (CADC 1945); Post v.
United States, 135 F. 1, 10 (CA5 1905).
   In apparent recognition of the fact that Davis relied on
the heightened mens rea applicable to the particular stat
10               DIXON v. UNITED STATES

                     Opinion of the Court

ute at issue, we held in Leland that this rule was not
constitutionally mandated, 343 U. S., at 797, and Con
gress overruled it by statute in 1984, requiring a defen
dant to prove his insanity by clear and convincing evi
dence, 98 Stat. 2057, codified at 18 U. S. C. §17(b).
Moreover, Congress has treated the defense of insanity
differently from that of duress not only by codifying it but
by requiring defendants who intend to rely on an insanity
defense to provide advance notice to the Government. See
Fed. Rule Crim. Proc. 12.2(a). Thus, even if the rule aris
ing from Davis may have once been relevant to an evalua
tion of other affirmative defenses, Congress’ differential
treatment of the insanity defense and its rejection of the
Davis rule are inconsistent with petitioner’s invitation to
follow Davis’ lead in this case.
   Indeed, petitioner’s reliance on Davis ignores the fact
that federal crimes “are solely creatures of statute,” Lipa
rota, 471 U. S., at 424, and therefore that we are required
to effectuate the duress defense as Congress “may have
contemplated” it in the context of these specific offenses,
United States v. Oakland Cannabis Buyers’ Cooperative,
532 U. S. 483, 491, n. 3 (2001) (internal quotation marks
omitted); see also id., at 499 (STEVENS, J., concurring in
judgment) (explaining that Court was addressing whether
the statute at issue foreclosed a necessity defense to spe
cific charges brought under the statute); Bailey, 444 U. S.,
at 410 (“We need not speculate now, however, on the
precise contours of whatever defenses of duress or neces
sity are available against charges brought under [18
U. S. C.] §751(a)”). The offenses at issue in this case were
created by statute in 1968, when Congress enacted the
Omnibus Crime Control and Safe Streets Act (hereinafter
Safe Streets Act or Act). See 82 Stat. 197. There is no
evidence in the Act’s structure or history that Congress
actually considered the question of how the duress defense
should work in this context, and there is no suggestion
                     Cite as: 548 U. S. ____ (2006)                    11

                          Opinion of the Court

that the offenses at issue are incompatible with a defense
of duress.6 Cf. Oakland Cannabis Buyers’ Cooperative,
532 U. S., at 491. Assuming that a defense of duress is
available to the statutory crimes at issue,7 then, we must
determine what that defense would look like as Congress
“may have contemplated” it.
  As discussed above, the common law long required the
defendant to bear the burden of proving the existence of
duress. Similarly, even where Congress has enacted an
affirmative defense in the proviso of a statute, the “settled
rule in this jurisdiction [is] that an indictment or other
pleading . . . need not negative the matter of an exception
made by a proviso or other distinct clause . . . and that it is
incumbent on one who relies on such an exception to set it
up and establish it.” McKelvey v. United States, 260 U. S.
353, 357 (1922); see also United States v. Dickson, 15 Pet.
141, 165 (1841) (calling this “the general rule of law which
has always prevailed, and become consecrated almost as a
maxim in the interpretation of statutes”). Even though the
Safe Streets Act does not mention the defense of duress, we
can safely assume that the 1968 Congress was familiar with
both the long-established common-law rule8 and the rule
——————
  6 While Congress’ findings in support of the Safe Streets Act show

that Congress was concerned because “the ease with which any person
can acquire firearms . . . is a significant factor in the prevalence of
lawlessness and violent crime in the United States,” §901(a)(2), 82 Stat.
225, it would be unrealistic to read this concern with the proliferation
of firearm-based violent crime as implicitly doing away with a defense
as strongly rooted in history as the duress defense, see, e.g., 4 W.
Blackstone, Commentaries on the Laws of England 30 (1769).
  7 We have previously made this assumption when addressing com

mon-law affirmative defenses, see United States v. Oakland Cannabis
Buyers’ Cooperative, 532 U. S. 483, 491 (2001); Bailey, 444 U. S., at 410,
and the parties give us no reason to question it here.
  8 Indeed, when a congressional committee did consider codifying the

duress defense, it would have had the courts determine the defense
“according to the principles of the common law as they may be inter
preted in the light of reason and experience.” S. 1437, 95th Cong., 2d
12                    DIXON v. UNITED STATES

                          Opinion of the Court

applied in McKelvey and that it would have expected federal
courts to apply a similar approach to any affirmative de
fense that might be asserted as a justification or excuse for
violating the new law.9
   This conclusion is surely more reasonable than peti
tioner’s hypothesis that Davis dramatically upset a well-
settled rule of law. Petitioner cites only one federal case
decided before 1968 for the proposition that it has been
well established in federal law that the Government bears
the burden of disproving duress beyond a reasonable
doubt. But that case involved a defendant’s claim that he
“lacked the specific intent to defraud required by the
statute for the reason that he committed the offense under
duress and coercion.” Johnson v. United States, 291 F. 2d
150, 152 (CA8 1961). Thus, when the Court of Appeals
explained that “there is no burden upon the defendant to
prove his defense of coercion,” id., at 155, that statement
is best understood in context as a corollary to the by-then
unremarkable proposition that “the burden of proof rests
upon the Government to prove the defendant’s guilt be
yond a reasonable doubt,” ibid. Properly understood,
Johnson provides petitioner little help in her uphill strug
gle to prove that a dramatic shift in the federal common-
law rule occurred between Davis and the enactment of the
Safe Streets Act in 1968.
   Indeed, for us to be able to accept petitioner’s proposi
tion, we would need to find an overwhelming consensus
among federal courts that it is the Government’s burden to
disprove the existence of duress beyond a reasonable
doubt. The existence today of disagreement among the
——————
Sess., §501 (1978).
  9 Duress, like the defense at issue in McKelvey, is an excuse that allows

an exception from liability. See, e.g., 2 LaFave §9.7, at 72 (“The ration
ale of the defense of duress is that the defendant ought to be excused
when he ‘is the victim of a threat that a person of reasonable moral
strength could not fairly be expected to resist’ ”).
                      Cite as: 548 U. S. ____ (2006)                     13

                           Opinion of the Court

Federal Courts of Appeals on this issue, however—the
very disagreement that caused us to grant certiorari in
this case, see n. 1, supra—demonstrates that no such
consensus has ever existed. See also post, at 6–8 (BREYER,
J., dissenting) (discussing differences in treatment of the
duress defense by the various Courts of Appeals). Also
undermining petitioner’s argument is the fact that, in
1970, the National Commission on Reform of Federal
Criminal Laws proposed that a defendant prove the exis
tence of duress by a preponderance of the evidence. See 1
Working Papers 278. Moreover, while there seem to be
few, if any, post-Davis, pre-1968 cases placing the burden
on a defendant to prove the existence of duress,10 or even
discussing the issue in any way, this lack of evidence does
not help petitioner. The long-established common-law
rule is that the burden of proving duress rests on the
defendant. Petitioner hypothesizes that Davis fomented a
revolution upsetting this rule. If this were true, one would
expect to find cases discussing the matter. But no such
cases exist.
   It is for a similar reason that we give no weight to the
publication of the Model Penal Code in 1962. As petitioner
notes, the Code would place the burden on the government
to disprove the existence of duress beyond a reasonable
doubt. See Model Penal Code §1.12, 10A U. L. A. 88
(2001) (hereinafter Model Penal Code or Code) (stating
that each element of an offense must be proved beyond a
reasonable doubt); §1.13(9)(c), at 91 (defining as an ele
——————
  10 In D’Aquino v. United States, 192 F. 2d 338, 358, n. 11 (CA9 1951), the
trial court instructed the jury that it would be warranted in acquitting the
defendant on the basis that she acted under duress “ ‘if you believe from
the evidence that the defendant committed these acts that the Govern
ment alleges . . . under a well grounded apprehension of immediate death
or serious bodily injury . . . .’ ” This instruction did not require the Gov
ernment to disprove duress beyond a reasonable doubt, and it seemingly
placed the burden on the defendant to prove the existence of duress.
14                DIXON v. UNITED STATES

                     Opinion of the Court

ment anything that negatives an excuse for the conduct at
issue); §2.09, at 131–132 (establishing affirmative defense
of duress). Petitioner argues that the Code reflects “well
established” federal law as it existed at the time. Brief for
Petitioner 25. But, as discussed above, no such consensus
existed when Congress passed the Safe Streets Act in
1968. And even if we assume Congress’ familiarity with
the Code and the rule it would establish, there is no evi
dence that Congress endorsed the Code’s views or incorpo
rated them into the Safe Streets Act.
  In fact, the Act itself provides evidence to the contrary.
Despite the Code’s careful delineation of mental states, see
Model Penal Code §2.02, 10A U. L. A., at 94–95, the Safe
Streets Act attached no explicit mens rea requirement to
the crime of receiving a firearm while under indictment,
§924(a), 82 Stat. 233 (“Whoever violates any provision of
this chapter . . . shall be fined not more than $5,000 or
imprisoned not more than five years, or both”). And when
Congress amended the Act to impose a mens rea require
ment, it punished people who “willfully” violate the stat
ute, see 100 Stat. 456, a mental state that has not been
embraced by the Code, see Model Penal Code §2.02(2), 10A
U. L. A., at 94–95 (defining “purposely,” “knowingly,”
“recklessly,” and “negligently”); Explanatory Note, p. 97
(“Though the term ‘wilfully’ is not used in the definitions
of crimes contained in the Code, its currency and its exis
tence in offenses outside the criminal code suggest the
desirability of clarification”). Had Congress intended to
adopt the Code’s structure when it enacted or amended
the Safe Streets Act, one would expect the Act’s form and
language to adhere much more closely to that used by the
Code. It does not, and, for that reason, we cannot rely on
the Model Penal Code to provide evidence as to how Con
gress would have wanted us to effectuate the duress de
fense in this context.
                 Cite as: 548 U. S. ____ (2006) 
                 15

                     Opinion of the Court


                            IV 

  Congress can, if it chooses, enact a duress defense that
places the burden on the Government to disprove duress
beyond a reasonable doubt. In light of Congress’ silence
on the issue, however, it is up to the federal courts to
effectuate the affirmative defense of duress as Congress
“may have contemplated” it in an offense-specific context.
Oakland Cannabis Buyers’ Cooperative, 532 U. S., at 491,
n. 3. In the context of the firearms offenses at issue—as
will usually be the case, given the long-established com
mon-law rule—we presume that Congress intended the
petitioner to bear the burden of proving the defense of
duress by a preponderance of the evidence. Accordingly,
the judgment of the Court of Appeals is affirmed.

                                                    It is so ordered.
                 Cite as: 548 U. S. ____ (2006)           1

                   KENNEDY, J., concurring

SUPREME COURT OF THE UNITED STATES
                         _________________

                         No. 05–7053
                         _________________


 KESHIA CHERIE ASHFORD DIXON, PETITIONER v.

               UNITED STATES

 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF

            APPEALS FOR THE FIFTH CIRCUIT

                        [June 22, 2006] 


  JUSTICE KENNEDY, concurring.
  No one disputes that, subject to constitutional con
straints, Congress has the authority to determine the
content of a duress defense with respect to federal crimes
and to direct whether the burden of proof rests with the
defense or the prosecution. The question here is how to
proceed when Congress has enacted a criminal statute, the
Omnibus Crime Control and Safe Streets Act of 1968, 82
Stat. 197 et seq. (hereinafter Safe Streets Act), without
explicit instructions regarding the duress defense or its
burden of proof. See ante, at 10.
  When issues of congressional intent with respect to the
nature, extent, and definition of federal crimes arise, we
assume Congress acted against certain background under
standings set forth in judicial decisions in the Anglo-
American legal tradition. See United States v. Bailey, 444
U. S. 394, 415, n. 11 (1980). Those decisions, in turn, con
sult sources such as legal treatises and the American
Legal Institute’s Model Penal Code. See, e.g., United
States v. Jimenez Recio, 537 U. S. 270, 275–276 (2003);
Salinas v. United States, 522 U. S. 52, 64–65 (1997). All of
these sources rely upon the insight gained over time as the
legal process continues. Absent some contrary indication
in the statute, we can assume that Congress would not
want to foreclose the courts from consulting these newer
2                 DIXON v. UNITED STATES

                    KENNEDY, J., concurring

sources and considering innovative arguments in resolving
issues not confronted in the statute and not within the
likely purview of Congress when it enacted the criminal
prohibition applicable in the particular case.
   While the Court looks to the state of the law at the time
the statute was enacted, see ante, at 12, the better reading
of the Court’s opinion is that isolated authorities or writ
ings do not control unless they were indicative of guiding
principles upon which Congress likely would have relied.
Otherwise, it seems altogether a fiction to attribute to
Congress any intent one way or the other in assigning the
burden of proof. It seems unlikely, moreover, that Congress
would have wanted the burden of proof for duress to vary
from statute to statute depending upon the date of enact
ment. Consistent with these propositions, the Court looks
not only to our precedents and common-law traditions, but
also to the treatment of the insanity defense in a 1984
statute and a proposal of the National Commission on
Reform of Federal Criminal Laws, even though they both
postdated the passage of the Safe Streets Act. See ante, at
10, 13.
   As there is no reason to suppose that Congress wanted
to depart from the traditional principles for allocating the
burden of proof, the proper approach is simply to apply
these principles to the context of duress. See, e.g.,
Schaffer v. Weast, 546 U. S. ___, ___ (2005) (slip op., at 6–
7) (where the plain text of the statute is “silent on the
allocation of the burden of persuasion,” we proceed to
consider the “ordinary default rule” and its exceptions).
The facts needed to prove or disprove the defense “lie
peculiarly in the knowledge of” the defendant. 2 K. Broun,
McCormick on Evidence §337, p. 475 (6th ed. 2006); see
ante, at 6. The claim of duress in most instances depends
upon conduct that takes place before the criminal act; and,
as the person who allegedly coerced the defendant is often
unwilling to come forward and testify, the prosecution
                Cite as: 548 U. S. ____ (2006)          3

                  KENNEDY, J., concurring

may be without any practical means of disproving the
defendant’s allegations. There is good reason, then, to
maintain the usual rule of placing the burden of produc
tion and persuasion together on the party raising the
issue. See 2 Broun, supra, §337; ante, at 6. The analysis
may come to a different result, of course, for other de
fenses.
   With these observations, I join the Court’s opinion.
                 Cite as: 548 U. S. ____ (2006)           1

                     ALITO, J., concurring

SUPREME COURT OF THE UNITED STATES
                         _________________

                         No. 05–7053
                         _________________


 KESHIA CHERIE ASHFORD DIXON, PETITIONER v.

               UNITED STATES

 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF

            APPEALS FOR THE FIFTH CIRCUIT

                        [June 22, 2006] 


   JUSTICE ALITO, with whom JUSTICE SCALIA joins,
concurring.
   I join the opinion of the Court with the understanding
that it does not hold that the allocation of the burden of
persuasion on the defense of duress may vary from one
federal criminal statute to another.
   Duress was an established defense at common law. See
4 W. Blackstone, Commentaries on the Laws of England
30 (1769). When Congress began to enact federal criminal
statutes, it presumptively intended for those offenses to be
subject to this defense. Moreover, Congress presumptively
intended for the burdens of production and persuasion to
be placed, as they were at common law, on the defendant.
Although Congress is certainly free to alter this pattern
and place one or both burdens on the prosecution, either
for all or selected federal crimes, Congress has not done so
but instead has continued to revise the federal criminal
laws and to create new federal crimes without addressing
the issue of duress. Under these circumstances, I believe
that the burdens remain where they were when Congress
began enacting federal criminal statutes.
   I do not assume that Congress makes a new, implicit
judgment about the allocation of these burdens whenever
it creates a new federal crime or, for that matter, when
ever it substantially revises an existing criminal statute.
2                DIXON v. UNITED STATES

                     ALITO, J., concurring

It is unrealistic to assume that on every such occasion
Congress surveys the allocation of the burdens of proof on
duress under the existing federal case law and under the
law of the States and tacitly adopts whatever the pre
dominant position happens to be at the time. Such a
methodology would create serious problems for the district
courts and the courts of appeals when they are required to
decide where the burden of persuasion should be allocated
for federal crimes enacted on different dates. If the alloca
tion differed for different offenses, there might be federal
criminal cases in which the trial judge would be forced to
instruct the jury that the defendant bears the burden of
persuasion on this defense for some of the offenses
charged in the indictment and that the prosecution bears
the burden on others.
   I would also not assume, as JUSTICE BREYER does, see
post, at 2–3, that Congress has implicitly delegated to the
federal courts the task of deciding in the manner of a
common-law court where the burden of persuasion should
be allocated. The allocation of this burden is a debatable
policy question with an important empirical component.
In the absence of specific direction from Congress, cf. Fed.
Rule Evid. 501, I would not assume that Congress has
conferred this authority on the Judiciary.
                 Cite as: 548 U. S. ____ (2006)            1

                     BREYER, J., dissenting

SUPREME COURT OF THE UNITED STATES
                         _________________

                         No. 05–7053
                         _________________


 KESHIA CHERIE ASHFORD DIXON, PETITIONER v.

               UNITED STATES

 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF

            APPEALS FOR THE FIFTH CIRCUIT

                        [June 22, 2006] 


   JUSTICE BREYER, with whom JUSTICE SOUTER joins,
dissenting.
   Courts have long recognized that “duress” constitutes a
defense to a criminal charge. Historically, that defense
“excuse[d] criminal conduct” if (1) a “threat of imminent
death or serious bodily injury” led the defendant to commit
the crime, (2) the defendant had no reasonable, legal
alternative to breaking the law, and (3) the defendant was
not responsible for creating the threat. United States v.
Bailey, 444 U. S. 394, 409–410 (1980); see also 2 W. LaFave,
Substantive Criminal Law §9.7(b), pp. 74–82 (2003) (here
inafter LaFave); ante, at 2, n. 1 (opinion of the Court). The
Court decides today in respect to federal crimes that the
defense must bear the burden of both producing evidence
of duress and persuading the jury. I agree with the major
ity that the burden of production lies on the defendant,
that here the burden of persuasion issue is not constitu
tional, and that Congress may allocate that burden as it
sees fit. But I also believe that, in the absence of any
indication of a different congressional intent, the burden of
persuading the jury beyond a reasonable doubt should lie
where such burdens normally lie in criminal cases, upon
the prosecution.
                          I
  My disagreement with the majority in part reflects my
2                 DIXON v. UNITED STATES

                     BREYER, J., dissenting

different view about how we should determine the rele
vant congressional intent. Where Congress speaks about
burdens of proof, we must, of course, follow what it says.
But suppose, as is normally the case, that the relevant
federal statute is silent? The majority proceeds on the
assumption that Congress wished courts to fill the gap by
examining judicial practice at the time that Congress
enacted the particular criminal statute in question. Ante,
at 10–14 (opinion of the Court). I would not follow that
approach.
   To believe Congress intended the placement of such
burdens to vary from statute to statute and time to time is
both unrealistic and risks unnecessary complexity, jury
confusion, and unfairness. It is unrealistic because the
silence could well mean only that Congress did not specifi
cally consider the “burden of persuasion” in respect to a
duress defense. It simply did not think about that secon
dary matter. Had it done so, would Congress have wanted
courts to freeze current practice statute-by-statute?
Would it have wanted to impose different burden-of-proof
requirements where claims of duress are identical, where
statutes are similar, where the only relevant difference is
the time of enactment? Why? Indeed, individual in
stances of criminal conduct often violate several statutes.
In a trial for those violations, is the judge to instruct the
jury to apply different standards of proof to a duress de
fense depending upon when Congress enacted the particu
lar statute in question? What if in this very case the
defendant’s boyfriend had given her drug money and
insisted (under threat of death) not only that she use some
of the money to buy him a gun, but that she launder the
rest? See 18 U. S. C. §1956 (2000 ed. and Supp. II); see
infra, at 6–7.
   I would assume instead that Congress’ silence typically
means that Congress expected the courts to develop bur
den rules governing affirmative defenses as they have
                 Cite as: 548 U. S. ____ (2006)           3

                    BREYER, J., dissenting

done in the past, by beginning with the common law and
taking full account of the subsequent need for that law to
evolve through judicial practice informed by reason and
experience. See Davis v. United States, 160 U. S. 469
(1895); McNabb v. United States, 318 U. S. 332, 341
(1943); ante, at 11, n. 8 (opinion of the Court) (proposed
general revision of the federal criminal code would have
instructed courts to determine the contours of affirmative
defenses “ ‘according to the principles of the common law
as they may be interpreted in the light of reason and
experience’ ”); 9 J. Wigmore, Evidence §2486, p. 291 (J.
Chadbourn rev. ed. 1981) (allocation of the burdens of
proof present courts with questions “of policy and fairness
based on experience in the different situations”). That
approach would produce uniform federal practice across
different affirmative defenses, as well as across statutes
passed at different points in time.
                             II
  My approach leads me to conclude that in federal crimi
nal cases, the prosecution should bear the duress defense
burden of persuasion. The issue is a close one. In Black-
stone’s time the accused bore the burden of proof for all
affirmative defenses. See 4 W. Blackstone, Commentaries
*201; Patterson v. New York, 432 U. S. 197, 201–202
(1977). And 20th-century experts have taken different
positions on the matter. The Model Penal Code, for exam
ple, recommends placing the burden of persuasion on the
prosecution.     ALI, Model Penal Code §1.12, p. 16,
§1.13(9)(c), p. 18, §2.09, pp. 37–38 (1985). The Brown
Commission recommends placing it upon the defendant.
National Commission on Reform of Federal Criminal
Laws, 1 Working Papers 278 (1970). And the proposed
revision of the federal criminal code, agnostically, would
have turned the matter over to the courts for decision.
S. 1722, 96th Cong., 1st Sess., §501 (1979). Moreover,
4                 DIXON v. UNITED STATES

                     BREYER, J., dissenting

there is a practical argument that favors the Govern
ment’s position here, namely that defendants should bear
the burden of persuasion because defendants often have
superior access to the relevant proof.
  Nonetheless, several factors favor placing the burden on
the prosecution. For one thing, in certain respects the
question of duress resembles that of mens rea, an issue
that is always for the prosecution to prove beyond a rea
sonable doubt. See In re Winship, 397 U. S. 358, 364
(1970); Martin v. Ohio, 480 U. S. 228, 234 (1987). The
questions are not the same. The defendant’s criminal
activity here was voluntary; no external principle, such as
the wind, propelled her when she acted. The Nico
machean Ethics of Aristotle, p. 54 (R. W. Browne transl.
1865). Moreover, her actions were intentional. Whether
she wanted to buy the guns or not, and whether she
wanted to lie while doing so or not, she decided to do these
things and knew that she was doing them. Indeed, her
action was willful in the sense that she knew that to do
them was to break the law. Ante, at 3–4 (opinion of the
Court); see also Ratzlaf v. United States, 510 U. S. 135,
136–137 (1994).
  Nonetheless, where a defendant acts under duress, she
lacks any semblance of a meaningful choice. In that sense
her choice is not free. As Blackstone wrote, the criminal
law punishes “abuse[s] of th[e] free will”; hence “it is
highly just and equitable that a man should be excused for
those acts, which are done through unavoidable force and
compulsion.” 4 Commentaries *27. And it is in this “force
and compulsion,” acting upon the will, that the resem
blance to lack of mens rea lies. Cf. Austin, Ifs and Cans, in
Proceedings of the British Academy 123–124 (1956) (not
ing difference between choosing to do something where one
has the opportunity and ability to do otherwise and choos
ing to do something where one lacks any such opportunity
or ability). Davis v. United States, supra, allocated the
                  Cite as: 548 U. S. ____ (2006)            5

                     BREYER, J., dissenting

federal insanity defense burden to the Government partly
for these reasons. That case, read in light of Leland v.
Oregon, 343 U. S. 790, 797 (1952), suggests that, even if
insanity does not always show the absence of mens rea, it
does show the absence of a “‘vicious will.’ ” Davis, supra, at
484 (citing Blackstone; emphasis added).
   For another thing, federal courts (as a matter of statu
tory construction or supervisory power) have imposed the
federal-crime burden of persuasion upon the prosecution
in respect to self-defense, insanity, and entrapment, which
resemble the duress defense in certain relevant ways. In
respect to both duress and self-defense, for example, the
defendant’s illegal act is voluntary, indeed, intentional;
but the circumstances deprive the defendant of any mean
ingful ability or opportunity to act otherwise, depriving
the defendant of a choice that is free. Insanity, as I said,
may involve circumstances that resemble, but are not
identical to, a lack of mens rea. And entrapment requires
the prosecution to prove that the defendant was “predis
posed” to commit the crime—a matter sometimes best
known to the defendant.
   As to self-defense, see First Circuit Pattern Criminal
Jury Instructions §5.04 (1998); United States v. Thomas,
34 F. 3d 44, 47 (CA2 1994); Government of Virgin Islands
v. Smith, 949 F. 2d 677, 680 (CA3 1991); United States v.
Harris, Nos. 95–5637, 95–5638, 1996 U. S. App. LEXIS
22040, *4–*5 (CA4, Aug. 27, 1996); United States v.
Branch, 91 F. 3d 699, 714, n. 1 (CA5 1996); Sixth Circuit
Pattern Criminal Jury Instructions §6.06 (2005); United
States v. Jackson, 569 F. 2d 1003, 1008, n. 12 (CA7 1978);
United States v. Pierre, 254 F. 3d 872, 876 (CA9 2001);
United States v. Corrigan, 548 F. 2d 879, 883 (CA10 1977);
United States v. Alvarez, 755 F. 2d 830, 842 (CA11 1985);
Bynum v. United States, 408 F. 2d 1207 (CADC 1968); see
also Mullaney v. Wilbur, 421 U. S. 684, 702, n. 30 (1975)
(noting this as the “ ‘majority rule’ ”).
6                 DIXON v. UNITED STATES

                     BREYER, J., dissenting

   As to insanity, see Davis, 160 U. S., at 486; Leland,
supra, at 797 (making clear that Davis determined burden
allocations as a matter of federal, but not constitutional,
law); but see 18 U. S. C. §17(b) (overruling this default
rule to place the burden on the defendant by clear and
convincing evidence). As to entrapment, see Jacobson v.
United States, 503 U. S. 540, 554 (1992) (reversing the
judgment affirming the conviction because “the prosecu
tion failed, as a matter of law, to adduce evidence to sup
port the jury verdict that petitioner was predisposed,
independent of the Government’s acts and beyond a rea
sonable doubt” to commit the crime). See also Patterson,
432 U. S., at 202 (noting that Davis “had wide impact on
the practice in the federal courts with respect to the bur
den of proving various affirmative defenses”); Patterson,
supra, at 231 (Powell, J., dissenting) (“[S]ince this Court’s
decision in Davis . . . federal prosecutors have borne the
burden of persuasion with respect to factors like insanity,
self-defense, and malice or provocation, once the defendant
has carried this burden of production”).
   Further, most federal courts, in respect to most federal
crimes, have imposed the burden of persuasion in respect
to the duress defense upon the Government, following
Johnson v. United States, 291 F. 2d 150, 155 (CA8 1961),
and authorities such as E. Devitt & C. Blackmar, Federal
Jury Practice and Instructions §13.14, p. 293 (2d ed.
1970), and the Federal Judicial Center Pattern Criminal
Jury Instructions §56 (1988). By the mid-1990’s, seven
circuits had squarely placed the burden of persuasion
upon the prosecution; one Circuit (the Fifth) placed the
burden on the defendant; and four (the Third, Fourth,
Eleventh, and District of Columbia) did not, as far as I can
tell, have a definitive practice. Compare United States v.
Arthurs, 73 F. 3d 444, 448 (CA1 1996); United States v.
Mitchell, 725 F. 2d 832, 836 (CA2 1983); United States v.
Campbell, 675 F. 2d 815, 821 (CA6 1982); United States v.
                 Cite as: 548 U. S. ____ (2006)           7

                    BREYER, J., dissenting

Talbott, 78 F. 3d 1183, 1186 (CA7 1996) (per curiam);
United States v. Campbell, 609 F. 2d 922, 925 (CA8 1979);
United States v. Hearst, 563 F. 2d 1331, 1336, and n. 2
(CA9 1977); United States v. Falcon, 766 F. 2d 1469, 1477
(CA10 1985), with United States v. Willis, 38 F. 3d 170,
179 (CA5 1994) (putting the burden on the defendant by a
preponderance).     Compare also First Circuit Pattern
Criminal Jury Instructions §5.05 (1998); Sixth Circuit
Pattern Criminal Jury Instructions §6.05 (1991); Seventh
Circuit Pattern Criminal Jury Instructions §6.08 (1998);
and Eighth Circuit Pattern Criminal Jury Instructions
§§3.09, 9.02 (2000), with Fifth Circuit Pattern Criminal
Jury Instructions §1.36 (2001). Petitioner adds, without
contradiction, that the States allocate the burden similarly
by a ratio of 2 to 1. Brief for Petitioner 32–34; Brief for
United States 38, n. 30.
  Beginning in 1991, the matter became more complicated
because the Ninth Circuit began to require the defendant
to bear the burden of proving duress in certain circum
stances. United States v. Dominguez-Mestas, 929 F. 2d
1379, 1382, 1384 (1991) (per curiam). And a few years
later the Third, Sixth, and Eleventh Circuits followed suit
in cases concerning a closely related justification defense.
See United States v. Dodd, 225 F. 3d 340, 347–350 (CA3
2000); United States v. Brown, 367 F. 3d 549, 555–556
(CA6 2004); United States v. Deleveaux, 205 F. 3d 1292,
1298-1300 (CA11 2000); Eleventh Circuit Pattern Crimi
nal Jury Instructions §16 (2003). But see Sixth Circuit
Pattern Criminal Jury Instructions §6.05 (2005) (stating
that the burden of proof issue for duress is undecided in
that Circuit).
  These latter cases, however, put the burden on the
defendant only where the criminal statute narrows its
mens rea requirement, i.e., the burden is the defendant’s
where the statute requires that the defendant act with
“knowledge” but not, suggest these courts, where the
8                 DIXON v. UNITED STATES

                     BREYER, J., dissenting

statute requires that the defendant act “willfully,” “inten
tionally,” or “voluntarily.” See, e.g., Dominguez-Mestas,
supra, at 1382, 1384; United States v. Meraz-Solomon, 3
F. 3d 298, 300 (CA9 1993); Ninth Circuit Pattern Criminal
Jury Instructions §§6.5, 6.6 (2003); but see United States
v. Fei Lin, 139 F. 3d 1303, 1307–1308 (CA9 1998). See
also Eleventh Circuit Pattern Criminal Jury Instructions
§16 (2003); United States v. Diaz, 285 F. 3d 92, 97 (CA1
2002) (indicating that this bifurcated rule might be appro
priate, but noting Circuit precedent to the contrary).
Similarly, the Tenth Circuit placed the burden of proving
duress upon the defendant in “strict liability” cases where
mens rea is not an element of the crime at all. United
States v. Unser, 165 F. 3d 755, 763–765 (CA10 1999).
   The apparent upshot is that four Circuits now place the
burden of persuasion on the prosecution across the board;
one places the burden on the prosecution if the statute
requires mens rea but not otherwise; and four have held or
suggested that the burden should be on the prosecution if
the statute requires an intentional or willful state of mind,
but not if the statute requires only knowledge. While the
Circuits are divided, apparently only one (the Fifth) agrees
with the position taken by the Court today.
   Further, while I concede the logic of the Government’s
practical argument—that defendants have superior access
to the evidence—I remain uncertain of the argument’s
strength. After all, “[i]n every criminal case the defendant
has at least an equal familiarity with the facts and in most
a greater familiarity with them than the prosecution.” Tot
v. United States, 319 U. S. 463, 469 (1943). And the strict
contours of the duress defense, as well as the defendant’s
burden of production, already substantially narrow the
circumstances under which the defense may be used. A
defendant may find it difficult, for example, to show duress
where the relevant conduct took place too long before the
criminal act. Cf. ante, at 2 (opinion of KENNEDY, J.). That is
                  Cite as: 548 U. S. ____ (2006)              9

                      BREYER, J., dissenting

because the defendant must show that he had no alternative
to breaking the law. Supra, at 1. And that will be the more
difficult to show the more remote the threat. See also La-
Fave, § 9.7, p. 77-79 (duress generally requires an “immedi
ate” or “imminent” threat, that the defendant “take advan
tage of a reasonable opportunity to escape,” and that the
defendant “terminate his conduct ‘as soon as the claimed
duress . . . had lost its coercive force’”). More important, the
need to prove mens rea can easily present precisely the same
practical difficulties of proof for the prosecutor. Suppose for
example the defendant claims that an old lady told him that
the white powder he transported across the border was
medicine for her dying son. Cf. United States v. Mares, 441
F. 3d 1152 (CA10 2006). See also Mullaney v. Wilbur, 421
U. S., at 702 (requiring the government to prove an absence
of passion in a murder conviction imposes “no unique hard
ship on the prosecution”).
   It is particularly difficult to see a practical distinction
between this affirmative defense and, say, self-defense.
The Government says that the prosecution may “be unable
to call the witness most likely to have information bearing
on the point,” namely, the defendant. Brief for United
States 21. But what is the difference in this respect be
tween the defendant here, who says her boyfriend threat
ened to kill her, and a battered woman who says that she
killed her husband in self-defense, where the husband’s
evidence is certainly unavailable? See also Jacobson, 503
U. S. 540 (entrapment; need to prove “propensity”). Re
gardless, unless the defendant testifies, it could prove
difficult to satisfy the defendant’s burden of production; and,
of course, once the defendant testifies, cross-examination is
possible.
   In a word, I cannot evaluate the claim of practicality
without somewhat more systematic evidence of the exis
tence of a problem, say, in those Circuits that for many
years have imposed the burden on the prosecutor. And, of
10               DIXON v. UNITED STATES

                    BREYER, J., dissenting

course, if I am wrong about the Government’s practical
need (and were my views to prevail), the Government
would remain free to ask Congress to reallocate the
burden.
   Finally, there is a virtue in uniformity, in treating the
federal statutory burden of persuasion similarly in respect
to actus reus, mens rea, mistake, self-defense, entrapment,
and duress. The Second Circuit, when imposing the bur
den of persuasion for duress on the prosecution, wrote that
differences in this respect create “a grave possibility of
juror confusion.” United States v. Mitchell, 725 F. 2d 832,
836 (1983) (Newman, J., joined by Feinberg, C. J., and
Friendly, J.). They risk unfairness as well.
   For these reasons I believe that, in the absence of an
indication of congressional intent to the contrary, federal
criminal law should place the burden of persuasion in
respect to the duress defense upon the prosecution, which,
as is now common in respect to many affirmative defenses,
it must prove beyond a reasonable doubt. With respect, I
dissent.
