(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 indictment 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 petitioner 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 specified in §§922(a)(6) and 924(a)(1)(D) and did not run afoul of due process by placing the burden on petitioner to establish duress by a preponderance 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 reasonable 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 murder 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 offense. 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 evidence. 

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 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, 490, n. 3. The Court can assume that, when 

passing the relevant 1968 Act, Congress was familiar with the longestablished common-law rule and the rule of McKelvey v. United 

States, 260 U. S. 353, 357—that the one relying on an affirmative defense must set it up and establish it—and would have expected federal courts to apply a similar approach to any affirmative defense or

excuse for violating the new law. To accept petitioner’s contrary hypothesis 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 opinion, 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, Washington, 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 indictment 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 Government 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 preponderance 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-

—————— 

1Cf., 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). 2There is no federal statute defining the elements of the duress defense. 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 avoidance 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 Petitioner 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 constitute 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 acquisition 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 

—————— 

3Although §922(n) does not contain a mens rea requirement, the relevant 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 considered in United States v. Bailey, 444 U. S. 394, 409–410 

(1980), may excuse conduct that would otherwise be punishable, 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 

—————— 

4As 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 “ ‘maliciously’ ”); Black’s Law Dictionary 968 (7th ed. 1999) (defining malice as

“[t]he intent, without justification or excuse, to commit a wrongful act”). 

5Professor 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 entrusted to the legislature, particularly in the case of federal crimes, which are solely creatures of statute.” Liparota 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 “knowingly,” §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 applicability 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 address 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 established 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.” Patterson, 432 U. S., at 202 (quoting 4 W. Blackstone, Commentaries *201); see also Martin v. Ohio, 480 U. S., at 235; 

Mullaney v. Wilbur, 421 U. S. 684, 693 (1975). This common-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 conviction 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 considered, 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 “‘presumes 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 comprehending 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 ourselves “unable to assent to the doctrine that in a prosecution 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 beyond 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 distinguish between right and wrong, the legal interpretation of every verdict of guilty as charged is that the 

jury believed from all the evidence beyond a reasonable doubt that the accused was guilty, and was therefore responsible, criminally, for his acts. How then 

upon principle or consistently with humanity can a 

verdict of guilty be properly returned, if the jury entertain 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 malice 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” (emphasis 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 ‘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 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 federal 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 persuasion 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 Congress overruled it by statute in 1984, requiring a defendant to prove his insanity by clear and convincing evidence, 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 arising from Davis may have once been relevant to an evaluation 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,” Liparota, 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 specific 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 necessity 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 

—————— 

6While 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). 7We have previously made this assumption when addressing common-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 interpreted 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 defense that might be asserted as a justification or excuse for 

violating the new law.

9 

This conclusion is surely more reasonable than petitioner’s hypothesis that Davis dramatically upset a wellsettled 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-thenunremarkable proposition that “the burden of proof rests 

upon the Government to prove the defendant’s guilt beyond a reasonable doubt,” ibid. Properly understood, 

Johnson provides petitioner little help in her uphill struggle to prove that a dramatic shift in the federal commonlaw rule occurred between Davis and the enactment of the 

Safe Streets Act in 1968. 

Indeed, for us to be able to accept petitioner’s proposition, 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). 9Duress, 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 rationale 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 existence 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 Government alleges . . . under a well grounded apprehension of immediate death

or serious bodily injury . . . .’” This instruction did not require the Government 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 evidence that Congress endorsed the Code’s views or incorporated 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 requirement, it punished people who “willfully” violate the statute, 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 existence 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 Congress would have wanted us to effectuate the duress defense 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 common-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 constraints, 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 understandings set forth in judicial decisions in the AngloAmerican legal tradition. See United States v. Bailey, 444 

U. S. 394, 415, n. 11 (1980). Those decisions, in turn, consult 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 writings 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 enactment. 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 production 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 defenses. 

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, whenever 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 predominant 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 allocation 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) (hereinafter 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 majority that the burden of production lies on the defendant, 

that here the burden of persuasion issue is not constitutional, 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 relevant 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 specifically consider the “burden of persuasion” in respect to a

duress defense. It simply did not think about that secondary 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 instances 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 defense depending upon when Congress enacted the particular 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 burden 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 criminal cases, the prosecution should bear the duress defense

burden of persuasion. The issue is a close one. In Blackstone’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 example, 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 Government’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 reasonable 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 Nicomachean 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 resemblance to lack of mens rea lies. Cf. Austin, Ifs and Cans, in 

Proceedings of the British Academy 123–124 (1956) (noting difference between choosing to do something where one

has the opportunity and ability to do otherwise and choosing 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 statutory 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 meaningful 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 “predisposed” 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 prosecution failed, as a matter of law, to adduce evidence to support the jury verdict that petitioner was predisposed, 

independent of the Government’s acts and beyond a reasonable 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 burden 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 circumstances. 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 Criminal 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,” “intentionally,” 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 appropriate, 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 LaFave, § 9.7, p. 77-79 (duress generally requires an “immediate” or “imminent” threat, that the defendant “take advantage 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 hardship 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 between the defendant here, who says her boyfriend threatened 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”). Regardless, 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 existence 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 burden 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.