This appeal calls upon us to confront a question explicitly reserved in
United States v. Diaz,
I. BACKGROUND
While the factual scenario portrayed at trial is littered with testimonial conflicts and is at some points shrouded in ambiguity, the facts relevant to this appeal are comparatively straightforward.
On July 27, 2003, defendant-appellant Jesse Leahy, a convicted felon, had an altercation with a group of teenagers near his mother’s home in Kezar Falls, Maine. According to Leahy, he withdrew from the scene, but the youths followed him and attempted forcibly to enter his mother’s house. Ostensibly fearing the maddened crowd, Leahy grabbed an Astra 9mm pistol that he knew his mother kept in a kitchen drawer. He emerged from the residence armed and confronted his tormentors.
During the ensuing imbroglio, Leahy admittedly fired the weapon. The protagonists’ versions of what happened differ materially. Leahy asserts that he did no more than fire warning shots into the ground to scare away attackers who were attempting to inflict serious bodily injury on him. Other witnesses describe Leahy as the aggressor and assert that he chased after the youths, shot towards them, and pistol-whipped two of their number.
In all events, the youths fled. Once that occurred, Leahy went back into the dwelling and hid the gun. Police soon arrived at the scene. After a twelve-hour standoff, they entered the premises and arrested Leahy. A search revealed not only the hidden pistol but also a Marlin rifle stashed in a pantry closet. Male DNA profiles found on the rifle were consistent with those found on the pistol (although no DNA was specifically matched to Leahy). In due season, a federal grand jury handed up an indictment that charged Leahy with being a felon in possession of a firearm. See 18 U.S.C. § 922(g)(1). The indictment referenced both the pistol and the rifle.
Leahy’s criminal record included felony convictions for assault and carrying a dangerous weapon. At trial, his then-counsel did not press for a stipulation that Leahy was a previously convicted felon (one exchange with the judge suggests that counsel may not have realized that he could compel the government to stipulate to this point). In the absence of a stipulation, the prosecutor was able to introduce independent evidence of the prior convictions.
Once both sides had rested, Leahy proffered a proposed instruction on self-defense — one that placed the burden of proof on the prosecution to disprove self-defense beyond a reasonable doubt. The government rejoined that the facts did not warrant a self-defense instruction. The district court took a middle path: over Le-ahy’s objection, it gave an instruction on “justification” (defined so as to encompass self-defense), in which it told the jury, in effect, that Leahy’s possession of a firearm would be justified (and, therefore, a guilty verdict would be unwarranted) if (i) Leahy was under an unlawful and present threat of death or serious bodily injury; (ii) he did not recklessly place himself in a situation in which he would be forced to engage in criminal conduct; (iii) he had no reasonable legal alternative but to engage in that conduct; and (iv) there was a direct causal relationship between his criminal conduct and the need to avoid the threatened harm. This instruction treated justification as an affirmative defense,
see United States v. Willis,
Following deliberations, the jury found Leahy guilty. At the disposition hearing, *405 the district court, finding that in the past Leahy had thrice been convicted of violent felonies, classified him as an armed career criminal. See 18 U.S.C. § 924(e). The court also determined that Leahy was subject to two separate sentencing enhancements, one for possessing the firearm in connection with an uncharged crime of violence and the other for obstruction of justice arising out of perjurious trial testimony. After making a series of other findings and computations, the court imposed a 262-month incarcerative sentence. This timely appeal followed.
II. BURDEN OF PROOF
Leahy’s flagship claim is that, once he had made a threshold showing of self-defense, the district court erred in requiring him to prove self-defense rather than requiring the government to negate his colorable claim. The proper allocation of the burden of proof on such a defense, however denominated, is an open question in this circuit with respect to felon-in-possession cases.
See Diaz, 285
F.3d at 97. The Constitution permits us to answer this question either way; there is no constitutional requirement that the burden of disproving self-defense reside with the prosecution.
See Patterson v. New York,
We introduce our analysis in case-specific terms. The principal issue at trial was whether Leahy, as a convicted felon, was legally justified in taking possession of the handgun. The government argued that Leahy was not so justified because he was the aggressor and, moreover, he was never under any realistic threat of imminent harm. Leahy, in contrast, argued that his bona fide fear of imminent harm justified him in taking possession of the handgun and defensively using it to repel his attackers.
Cf. United States v. Holliday,
The federal felon-in-possession statute itself, 18 U.S.C. § 922(g), makes no express provision for any affirmative defenses. Thus, the logical starting place is the Supreme Court’s recent decision in
Dixon v. United States,
—■ U.S.-,
Although the
Dixon
Court, for this purpose, used the term “duress,” that usage
*406
appears to have been a carry-over of the usage employed below.
See United States v. Dixon,
This inferential process, which requires courts to draw on common law doctrines, has produced confusion over nomenclature.
See, e.g., United States v. Panter,
In hopes of distinguishing
Dixon,
Leahy beseeches us to disambiguate self-defense from the broader category of justification. He emphasizes that the
Dixon
Court looked at the state of the law in 1968 (when Congress first conceived the federal
*407
felon-in-possession statute)
5
to help determine what allocation of the burden of proof Congress most likely would have chosen had it inserted a duress defense into the statutory text.
See Dixon,
Leahy’s premise is incorrect. Although seven Justices joined the opinion of the
Dixon
Court, Justice Kennedy wrote a concurring opinion that distanced him from the date-centric methodology employed in that opinion and wrote that, as a general matter, “we can assume that Congress would not want to foreclose the courts from consulting ... newer sources and considering innovative arguments.”
Dixon,
It can also be argued that, as an historical matter, self-defense circa 1968 was generally limited to assaultive crimes.
See 2
Wayne R. LaFave, Substantive Criminal Law § 10.4(a), at 143 (2d ed.2003); George E. Dix & M. Michael Sharlot, Criminal Law: Cases and Materials 776 (5th ed.2002).
6
This strong correlation between self-defense and assaultive crimes is evident from Leahy’s citation to
Mullaney. See Mullaney,
*408
We need not dwell on the distinction between assaultive and non-assaultive crimes, for there is a more fundamental flaw in Leahy’s thesis. The crimes historically associated with self-defense (homicide, for example) all carry substantial mens rea requirements. The federal felon-in-possession statute requires proof that the defendant
knowingly
possessed a firearm.
7
See United States v. Carpenter,
The absence of a mens rea requirement has obvious implications. In a felon-in-possession case (unlike in, say, an assaultive crime), evidence of facts concerning self-defense neither contradicts nor tends to disprove any element of the charged crime.
Cf. Dixon,
Most of the other courts that have considered this question have come to the same conclusion. Four of our sister circuits have squarely confronted the issue of allocating the burden of proof on a justification defense other than duress to federal felon-in-possession charges, where proof of the defense would not negate any of the elements of the charged crime. Three of the four have assigned the burden of proving such a defense to the defendant.
See Beasley,
Leahy argues that pragmatic considerations counsel in favor of assigning the burden of proof to the government. We think that these considerations tilt the other way. When self-defense is an issue in a felon-in-possession case, the defendant is likely to have greater access to the relevant facts than the government.
See Dele-veaux,
To sum up, we confirm the suggestion previously made in Holt and Holliday, *409 and add our voice to the weight of authority by holding that, in some circumstances, justification — -a term that we define to include, inter alia, self-defense — can comprise an affirmative defense to a federal felon-in-possession charge. Furthermore, we think it highly unlikely that Congress, in enacting the federal felon-in-possession law, intended to require the government to prove beyond a reasonable doubt the existence of a fact that it did not specify as an element of the offense. Consequently, we hold that in a federal felon-in-possession prosecution, there is no sound basis for treating that defense differently from other justification defenses. It follows that a defendant who asserts self-defense in such a case must carry the devoir of persuasion on that defense by a preponderance of the evidence.
In that regard, we adopt the four-part framework for justification discussed by the Supreme Court in
Dixon,
It is evident from what we have said that Leahy’s principal claim of error fails. We think it is prudent, however, to add two caveats. First, this holding is limited to justification defenses that do not go to the elements of the felon-in-possession offense. We leave open the possibility that a defense within the rubric of justification might negate an element of the felon-in-possession offense. In that event, the burden of disproving the defense would rest on the prosecution. Second, although we believe it is useful to speak of a single justification defense, we caution that different factual scenarios may require variations in the phrasing of the four-factor test. For example, the first factor, which requires that the defendant be under a present and unlawful threat of death or serious bodily injury, will require modification in cases in which the defendant allegedly acts in defense of a third party. Those nuances remain to be developed in future cases.
III. UNANIMITY
The indictment in this case contained only a single count. That count mentioned two guns — the pistol and the rifle — and the government adduced evidence at trial about both weapons. The jury returned a general verdict. Based on this collocation of circumstances, Leahy suggests that he may have been convicted because some jurors believed that he possessed the rifle while others believed that he possessed the pistol but did not act in self-defense. To safeguard against this possibility, his thesis runs, the district court should have instructed the jury that unanimity as to the identity of the weapon unlawfully possessed was required.
Leahy’s concern for unanimity is of recent vintage: he did not request such an instruction below. The issue is, therefore,
*410
forfeited.
See, e.g., United States v. Gomez,
The plain error hurdle is high.
United States v. Hunnewell,
It is settled law that “Congress did not intend the possession of a particular firearm to be an element of a § 922(g)(1) violation.”
United States v. Verrecchia,
Were this objection preserved, we would be forced to delve into the geography of the relevant unit of prosecution and determine whether the pistol (taken from a kitchen drawer one evening) and the rifle (stowed in the pantry but perhaps handled at some indeterminate point) were sufficiently related in “time” and “place”. But the objection was not preserved, and Ver-recchia is tenebrous as to the temporal and spatial contours of the “relevant unit of prosecution.” That combination defeats a claim that an obvious error occurred. Hence, Leahy cannot satisfy the strictures of plain error review.
IV. INEFFECTIVE ASSISTANCE
Leahy next complains that his trial counsel did not offer to stipulate to the fact the he was a previously convicted felon — an omission that opened the door for the government to introduce evidence of the unattractive particulars of Leahy’s prior misdeeds. Since the government would have had no choice but to enter into such a stipulation upon a timely request,
see Old Chief v. United States,
To be sure, there is a narrow exception to this rule for cases in which the record is adequately developed to permit reasoned consideration of the claim.
See, e.g., United States v. Natanel,
V. SENTENCING
As a tail-end matter, Leahy raises three objections to his sentence. We address them sequentially.
*411 A. Armed Career Criminal.
As said, the district court sentenced Le-ahy under the Armed Career Criminal Act (ACCA), 18 U.S.C. § 924(e). The court adopted this taxonomy after having found that Leahy’s record included the necessary predicate: three prior convictions for violent felonies. See id. As a result of this determination, Leahy faced a fifteen-year mandatory minimum sentence, see id., and automatically incurred elevated criminal history and offense level placements, see USSG § 4B1.4.
Pertinently, ACCA defines a “violent felony” as a crime punishable by “imprisonment for a term exceeding one year” that “involves conduct that presents a serious potential risk of physical injury to another.” 18 U.S.C. § 924(e)(2)(B). Three such felony convictions are required to trigger the statute, and Leahy asserts that one of his three prior convictions— namely, a Massachusetts conviction for indecent assault and battery, see Mass. Gen. Laws ch. 265, § 13H 9 — does not qualify and, therefore, ACCA does not apply.
The determination of whether a particular crime is a violent felony is a question of law and, thus, engenders de novo review.
See United States v. Bishop,
The methodology for deducing whether a given offense constitutes a violent felony derives from
Taylor v. United States,
The district court concluded that, under this approach, all section 13H convictions were convictions for violent felonies. In reaching this conclusion, the court relied heavily on
Sutherland v. Reno,
Leahy attempts to distinguish
Sutherland
by noting that the opinion deals with the definition of “crime of violence” found in 18 U.S.C. § 16(b). Building on that foundation, he points out that while ACCA’s definition of “violent felony” has been deemed substantively identical to the definition of “crime of violence” used in the federal sentencing guidelines,
see United
*412
States v. Jackson,
Leahy’s argument does not withstand scrutiny. To begin, both
Leocal
and
Agu-iar
treat section 4B1.2 as reaching conduct
beyond
the scope of section 16(b).
See Leocal,
This conclusion is buttressed by our decision in
United States v. McVicar,
Leahy makes much of the fact that Massachusetts does not include indecent assault and battery in its own list of “sexually violent offenses.”
See
Mass. Gen. Laws ch. 6, § 178C. That fact is of little moment. “Because a state’s classification of a crime generally reflects different policy considerations than the federal classification, it is simply not relevant to the determination of whether a crime is a ‘violent felony,’ which, under federal law, is based on an assessment of the risk of physical injury associated with' the typical conduct underlying that crime.”
United States v. Sacko,
The short of it is that the lower court correctly sentenced Leahy as an armed career criminal.
B. Judicial Factfinding.
When a defendant is found to be an armed career criminal, USSG § 4B1.4 applies to his case. By reason of that paradigm, the defendant faces increases in both his offense level and his criminal history category if he is found to have used or possessed the firearm in connection with a crime of violence (whether charged or un
*413
charged).
See Holliday,
Leahy argues that, under the Sixth Amendment, he was entitled to have these determinations made by a jury beyond a reasonable doubt. He frankly acknowledges that this argument contradicts the combined holding of
United States v. Watts,
This argument need not detain us. We have recently held in precisely analogous circumstances (involving a USSG § 4B1.4 enhancement predicated upon an uncharged crime of violence) that “even after Booker, [there is no need that] the facts underlying the enhancement be found by a jury. Under the advisory guidelines regime, the district court can use the preponderance of the evidence standard to determine whether an enhancement applies.” Holliday, 457 at 130. This holding obliterates Leahy’s objection.
C. Obstruction of Justice.
Finally, Leahy objects to a two-level sentencing enhancement for obstruction of justice.
See
USSG § 3C1.1. In his view, the enhancement rests on shaky ground because the sentencing court did not make findings that identified perjurious statements with particularity.
See United States v. Dimnigan,
Our review of the record indicates that the district court in fact identified some aspects of Leahy’s testimony that it found incredible. Still, it is unnecessary to probe that point; the short, dispositive rejoinder to Leahy’s plaint is that any error was harmless. We explain briefly.
On the basis of its determination that Leahy had obstructed justice, the district court adjusted his offense level from 28 to 30. This adjustment became irrelevant, however, when the court found Leahy to have been an armed career criminal who possessed a firearm in connection with an uncharged crime of violence.
See supra
Parts V(A)-(B). That finding triggered an overriding offense level of 34, which came into play without regard to other enhancements.
See
USSG § 4B1.4(b). The superimposition of this enhancement rendered the putative enhancement for obstruction of justice moot.
See United States v. Cruz,
VI. CONCLUSION
We need go no further. For aught that appears, Leahy was fairly tried, justly convicted, and lawfully sentenced. Consequently, we uphold the conviction and sentence, without prejudice, however, to Le-ahy’s right, should he so elect, to revive his ineffective assistance of counsel claim on collateral review.
Affirmed.
Notes
. The case at hand does not involve a claim of self-defense via-á-vis a law enforcement officer. Such cases may present special considerations and, thus, are beyond the scope of this opinion.
. In Dixon, the charges were receiving a firearm while under indictment, 18 U.S.C. § 922(n), and making false statements in connection with the acquisition of a firearm, id. § 922(a). The Court did not discuss these charges separately, and the decision would appear to be fully applicable to violations of 18 U.S.C. § 922(g).
. One court has crafted an affirmative defense of “innocent possession,” independent of any justification defense.
See United States v. Mason,
. In a post-argument letter,
see
Fed. R.App. P. 28(j), Leahy has directed us to a terse exchange between government counsel and the Supreme Court during oral argument in Dis-
on.
That exchange raised the possibility of establishing different burden-of-proof allocations for duress and self-defense. Transcript of Oral Argument,
Dixon v. United States,
. The origin of section 922 can be found in the Omnibus Crime Control and Safe Streets Act of 1968, Pub.L. No. 90-351, § 922, 82 Stat. 197, 228. That statute included an early precursor to section 922(g)(1).
See id.
at § 922(f),
. While some modern innovation has expanded the breadth of self-defense,
see, e.g., Boget
v.
State,
. The justification defense asserted by Leahy in this case does not go to knowledge; Leahy readily concedes that he knowingly seized the handgun.
. As to the second element of the framework, the court charged the jury that Leahy had to prove that he did not “recklessly” place himself in a situation in which he would be forced to engage in criminal conduct. The authorities are divided on the question of whether the second element extends to negligence as well as recklessness.
Compare, e.g., Dixon,
. The provision reads in relevant part:
Whoever commits an indecent assault and battery on a person who has attained age fourteen shall be punished by imprisonment in the state prison for not more than five years, or by imprisonment for not more than two and one-half years in a jail or house of correction.
. Both sides debate the significance to this issue of our decision in
United States v. Sherwood,
