Preserving the Presumption of Innocence: A Reverse 403 Test for Rule 404

by Sean Ignatuk & Jake Wasinger | June 16, 2026

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Introduction

Rule 404(a) of the Federal Rules of Evidence prohibits the admission of character evidence to prove a person acted in accordance with that character. In the context of criminal prosecutions, this rule helps preserve the presumption of innocence of a defendant by forbidding the admission of propensity reasoning that would otherwise unfairly prejudice a jury at the outset of a trial. Nowhere is this protection more important than when a prosecutor attempts to admit evidence of a defendant’s prior convictions. Although 404(b) was initially meant to clarify the limits of 404(a)’s exclusionary rule, it has now rendered the rule impotent against the very concerns that motivated its original drafting. Even when 404(b) is properly applied in admitting prior convictions, courts ascribe prior convictions much more probative weight than they deserve and assume they are much less prejudicial to a jury than they often are. These issues with 404(b) are brushed aside by courts who point to limiting instructions as a panacea. But limiting instructions have proven to be cold comfort to a criminal defendant’s presumption of innocence.

We propose a requirement that a reverse 403 test be met before a court can admit evidence of prior convictions against a criminal defendant. Two premises motivate our proposal. First, prior convictions ought to be presumptively prohibited and a burden should be on the proponent to argue admissibility under a balancing test. Second, a reverse 403 requirement, rather than a simple balancing test, is appropriate because the issues endemic to the admission of prior convictions under 404(b) are serious enough that a substantial barrier to admissibility is justified. Further, reverse 403 tests have proven workable within Rules 412 and 609.

The Virtues of Rule 404

Rule 404 stands for the proposition that a defendant should “be tried for what he did, not who he is.”^[1] It is a flat prohibition, not a balancing test, out of concern that courts and jurors may not properly weigh the probative value or prejudicial effect of character evidence.^[2] As the Supreme Court wrote in Michelson v. United States:

“The inquiry [into a defendant’s character] is not rejected because character is irrelevant; on the contrary, it is said to weigh too much with the jury, and to so overpersuade them as to prejudge one with a bad general record and deny him a fair opportunity to defend against a particular charge.”^[3]

This general prohibition is perhaps most important in the context of defendants who have a history of prior convictions. The D.C. Circuit once remarked in United States v. Daniels that when “evidence of prior crimes reaches the jury, it is most difficult, if not impossible, to assume continued integrity of the presumption of innocence.”^[4] Similarly, in Spencer v. Texas, Chief Justice Warren wrote in dissent, recognizing that the admission of prior convictions could “jeopardize[] the presumption of innocence of the crime currently charged.”^[5] Indeed, the presumption of innocence for a defendant is often shattered the moment a juror hears of an offensive prior conviction. The Tenth Circuit once took this sentiment even further in remarking that it is “an obvious truth” that “once prior convictions are introduced, the trial is, for all practical purposes, completed and the guilty outcome follows as a mere formality.”^[6] The 10th Circuit here likely overstates the case, but we are confident that, as Professor Paul S. Milich wrote in The Degrading Character Rule in American Criminal Trials, jurors exposed to prior criminal convictions are “unlikely to extend the presumption of innocence as vigorously.”^[7] By our reading, 404 recognizes that, since the presumption of innocence is on the line, evidentiary rules ought to err on the safe side.

404(b) and Its Discontents

Rule 404(b) clarifies that prior acts—including prior convictions—may be admitted when offered for a nonpropensity purpose such as proving a defendant’s motive, intent, knowledge, plan, or absence of mistake. For example, imagine that a defendant accused of hacking into the FBI’s databases had previously won a “hackathon” (an intense competition between computer hackers). The hacker’s victory might be admitted to prove that they had sufficient knowledge of computer hacking to breach the FBI’s firewalls. This is likely the sort of unproblematic outcome the drafters intended for 404(b). But in practice, 404(b)’s clarification of 404(a)’s general prohibition quickly turns into a functional erasure of the rule.

Two crucial issues plague 404(b). First, 404(b) is frequently misapplied. Often, it is taken to be a list of exceptions to 404(a) that tolerates propensity reasoning in the process of proving a nonpropensity purpose. The Advisory Committee to the Federal Rules of Evidence noted in 2025 that “404(b) evidence is commonly admitted” in circumstances that “arguably depend for their relevance on some propensity inference.”^[8] This kind of reasoning is a misapplication of 404(a) because any propensity inference—including when obscured within a larger chain of reasoning—is prohibited.

The second crucial issue with 404(b) is that, despite the exclusionary language of 404(a)—suggesting a general exclusion of prior act evidence—most circuits interpret 404(b) to render the character evidence rule functionally “inclusionary” in the sense that the “general consensus is a preference for admissibility…[of] prior acts evidence.”^[9] This inclusionary assumption of Rule 404(b) manifests in a common problem: even when 404(b) is properly applied, it often produces outcomes that seem antithetical to Rule 404(a)’s base concerns. This is particularly true in the context of prior convictions. Consider the following examples of circuit cases cited as exemplars of 404(b) in Wright & Miller’s Federal Practice & Procedure.^[10] In United States v. Nelson, the Ninth Circuit reasoned that evidence of a defendant’s prior convictions and the details of his enrollment in a sexual offender treatment program “was admissible [under 404(b)] to show motive that Nelson might be inclined to seek child pornography.”^[11] Similarly, in United States v. Wallace, the Tenth Circuit held that evidence of a prior gun purchase was admissible to show opportunity for obtaining an illegal AK-47.^[12] In United States v. Foster, the Ninth Circuit found a prior drug conviction admissible for proving a defendant’s “intent to possess with intent to distribute” drugs found around him.^[13]

Arguably, these cases wrongly applied 404(b). Perhaps the convictions should have failed a 403 analysis or the chains of inferences used to ground their 404(b) analysis necessarily relied on propensity reasoning. So, on the one hand, if these cases are wrongly decided on 404(b)’s own terms, they suggest that 404(b) is frequently misapplied because these outcomes are not aberrations in the jurisprudence.^[14] On the other hand, if these cases are correctly decided, they are demonstrative of how far the outcome has strayed from the first principles of 404(a). The spectre of propensity reasoning lurks, and the defendant is likely to be unfairly prejudiced by his prior convictions. Either way, these cases are emblematic of what Professor Paul S. Milich calls the “inexorable expansion” of Rule 404(b) that “ultimately swallow[s] all but remnants of the prohibition against character evidence.”^[15] Here, we come to understand that 404(b)’s nonpropensity uses can be functionally indistinguishable from forbidden propensity reasoning.

Inefficacy of Limiting Instructions

Courts are far less pessimistic about 404(b), often pointing to limiting instructions as a way to cure its unfairly prejudicial trends.^[16] But it would be breaking no new ground to express skepticism of limiting instructions.^[17] Justice Robert Jackson once described “[t]he naive presumption that prejudicial effects can be overcome by instructions to the jury, [which] all practicing lawyers know to be unmitigated fiction.” Much of this is common sense; telling juries to “ignore that” is an unfortunately predictable way to perk up their ears. Even still, courts routinely reference their faith in these instructions when admitting evidence under 404(b).^[18] Although they offer a convenient legal fiction for courts, a criminal defendant’s presumption of innocence finds no refuge. We take the position that any rule which results in a weakening of the presumption of innocence is a rule that sorely needs revision.

Proposed Revision

There are several potential solutions to the problems of 404(b). First, amending Rule 404(b) to clarify that it excludes hidden and nested inferences of propensity reasoning could go far to resolve 404(b)’s misapplication. Although this is promising, it would address only the misapplication of 404(b), which is half of the problem. We might also consider eliminating the systemic faith in limiting instructions, which might do much to ameliorate the other issues of 404(b) insofar as it would strengthen the application of 403 balancing. But this would hardly be a novel proposal. Limiting instructions are deeply ingrained in our legal system and have long been critiqued. We infer that the present lack of a revision to limiting instructions suggests its own implausibility.

Another solution to the problems of 404(b) could be in amending the text of 404(b) itself. Some have suggested requiring that admission of prior acts pass a simple probative-prejudicial balancing test, rather than 403.^[19] Because a simple balancing test may not go far enough, a higher bar could do more to protect criminal defendants. The Advisory Committee should insert a reverse 403 test into 404(b), requiring that evidence of a defendant’s prior conviction be admitted only when it is substantially more probative than prejudicial.

Our proposal has two central premises. First, there should be a general assumption against the admissibility of a defendant’s prior convictions, and the burden of demonstrating probative value should be on the proponent. Second, the issues with character evidence—particularly for prior conviction evidence—have proven so substantial as to warrant the creation of an equally substantial barrier to admission.

Currently, the defendant has the burden of arguing against the admissibility of a prior conviction because such evidence, when used for a nonpropensity purpose, is assumed admissible once past the low bar of 401. This is a mistake. The base concern of Rule 404(a) is that character evidence poses a threat of unfair prejudice. So to put the burden of opposing 404(b)’s often prejudicial admissions on the nonmover is a strange fit. If we take the concerns of prejudice seriously, the burden to affirmatively argue for the admissibility of the evidence, weighing its probative and prejudicial effects, should be on the proponent. Thus, the default becomes prohibiting the evidence, rather than admitting it.

This is not a novel proposition. Some scholars have called for a reverse balancing test to be imposed on 404(b), with the Reporter of the Advisory Committee noting in 2025 that “adding a reverse balancing test to Rule 404(b) to protect criminal defendants would be” an “optimal fix” to the problems that plague 404(b).^[20] This revision has yet to be made, and we take the position that a simple reverse balancing test is not enough.

Few have entertained the possibility of imposing a higher barrier than a simple reverse balancing test. A reverse 403 test, as opposed to a simple balancing test, is appropriate due to the significant issues of 404(b). We confine the application of this reverse 403 test to prior convictions because it stands as the most compelling case against the status quo and is more politically feasible.

Even when it is correctly applied, 404(b) presents substantial issues: prior conviction evidence is given much more probative weight than it deserves, and it is assumed to be much less prejudicial than it is. Ostensibly, these sentiments of prejudice and probative value are immovable; we can’t convince a court to find prior convictions more prejudicial any more than we could convince them to alter their perception of the efficacy of limiting instructions. Thus, the addition of a “substantial” threshold to the reverse-balancing test is an adequate counterbalance to the substantial problems with 404(b). This high barrier would be in keeping with an evidentiary posture that is wary of any threats to the presumption of innocence. To the extent that this high barrier might bar the admission of some evidence that might seem intuitively important for prosecution, we are comfortable with that sacrifice. This play-it-safe approach would not be an aberration in the panoply of rights afforded to a criminal defendant. The exclusionary rule, Miranda warnings, and the beyond a reasonable doubt burden of proof are potent examples. In this context, affording more protection than might be necessary in some cases is consistent with the cautionary tradition of criminal rights. Because the presumption of innocence is critically implicated in the admission of 404(b) prior conviction evidence, it should be no different.

The imposition of a reverse 403 balancing test to 404(b) would not be as novel as it may first seem. Reverse 403 tests appear several times in the FRE. Indeed, the concerns that animate our proposal share some similarity with the reverse 403 requirements of Rules 609 and 412. Rule 609(b) places a reverse 403 test on the admission of a criminal conviction to impeach a witness when the conviction is over ten years old. The imposition of this high requirement of admissibility reflects an intuition that a jury would put too much weight on a person’s old prior convictions and that old convictions are generally of little utility in deciding a person’s credibility. As the committee notes, these convictions “will be admitted very rarely and only in exceptional circumstances.” But there is no clear reason why prior convictions should interact with the credibility of witnesses in a different way than they should interact with a defendant’s presumption of innocence. The FRE ought to extend at least the same skepticism of prior convictions in 609 to 404, especially since the presumption of innocence is implicated in the latter.

Rule 412 offers another illustrative example. It limits the admission of evidence in a civil case when that evidence is offered to prove a victim’s unrelated sexual behavior or sexual predisposition to only that which can pass a reverse 403 test. This high barrier to admission was drafted to counter inappropriate victim blaming and intimidation that scares off critical testimony. This rule reflects the intuition that a victim’s unrelated sexual proclivities are not the sort of evidence that our justice system should allow a jury to contemplate; it is sensitive and too often leads to unfair prejudice against a witness. In that way, the concerns of 404 find some similarity. If a reverse 403 test has proven an appropriate remedy for the concerns of 412, then perhaps it also shows promise as a workable solution to the problems of 404.

Conclusion

Our proposal has some limitations that warrant further development. Courts that misapply 404(b), as it is now, may also misapply 404(b) with a reverse 403 test. We consider this possibility less likely, however, because the higher textual bar will be more difficult to ignore. Additionally, it is an open question exactly how courts would apply these reverse 403 tests across a variety of cases. Further development of these outcomes would prove helpful in fleshing out this proposal. Suffice it to say that with this proposal, we wish only to begin the conversation of what the 404 could look like.

The criminal justice system is at its best when it tries a defendant for “what he did, not who he is.” But 404(b) gets in the way of this. Our system nominally presumes that defendants are innocent and that once they serve their time are rehabilitated. It is a strange fit, then, to readily admit evidence of prior convictions and bad acts that play on stereotypes in the mind of a juror. As it stands, 404(b) renders 404 impotent against the very concerns that motivated its original drafting. Thus, we propose the creation of a substantial barrier to admission by requiring that all evidence admitted under 404(b) pass a reverse 403 test. We think that to be a promising frontier worthy of exploring. But prudence instructs we first target the most egregious applications of 404(b), which we find in the admission of prior conviction evidence. When the presumption of innocence is on the line, we ought to err on the side of caution. Thus, our proposed language hopes to codify what ought to be practice: a “spirit of liberty which is not too sure that it is right.”^[21]

^[1] United States v. Myers, 550 F.2d 1036, 1044 (5th Cir. 1977).

^[2] See Charles Alan Wright & Kenneth W. Graham, Jr., Federal Practice & Procedure Vol. 22B §5243 Evidence (2d ed. 1982) (discussing 404 policy concerns that "it seems dangerous to allow the jury to infer much from a single act").

^[3] Michelson v. United States, 335 U.S. 469, 476 (1948).

^[4] United States v. Daniels, 770 F.2d 1111, 1118 (D.C. Cir. 1985); see also In re Winship, 397 U.S. 358, 363. (1970) (discussing the presumption of innocence as “that bedrock axiomatic and elementary principle whose enforcement lies at the foundation of our criminal law”).

^[5] Spencer v. Texas, 385 U.S. 554, 575 (1967) (Warren, C.J., dissenting).

^[6] United States v. Burkhart, 458 F.2d 201, 204 (10th Cir. 1972).

^[7] Paul S. Milich, The Degrading Character Rule in American Criminal Trials, 47 Ga. L. Rev. 775, 785 (2013).

^[8] Advisory Comm. on Evidence Rules, Agenda Book, 18 (May 2, 2025), https://www.uscourts.gov/sites/default/files/document/2025-05-02_evidence_committee_meeting_minutes_final.pdf.

^[9] David A. Sonenshein, The Misuse of Rule 404(b) on the Issue of Intent in the Federal Courts, 45 Creighton L. Rev. 215, 236 (2011); see also Daniel J. Capra & Liesa L. Richter, Character Assassination: Amending Federal Rule of Evidence 404(b) to Protect Criminal Defendants, 118 Colum. L. Rev. 769 (2018) (​​referencing the “well-documented permissive admission of the prior bad acts”).

^[10] Wright & Graham, supra note 2.

^[11] United States v. Nelson, 38 Fed.Appx. 386 (9th Cir. 2002).

^[12] United States v. Wallace, 647 Fed.Appx. 842 (10th Cir. 2016).

^[13] United States v. Foster, 664 Fed.Appx. 644 (9th Cir. 2016).

^[14] See generally Charles A. Wright & Arthur R. Miller, 22 Federal Practice & Procedure §5247.3-47.4; See also Hillel J. Bavli, An Objective-Chance Exception to the Rule Against Character Evidence, 74 Ala. L. Rev. 121, 136 (2nd ed. 2022) (noting that, in light of 404(b), Rule 404 “cannot be said to exclude impermissible character evidence with any predictability”).

^[15] Milich, supra note 7, at 778.

^[16] See United States v. Snype, 441 F.3d 119, 129 (2d Cir. 2006) (noting that “the law recognizes a strong presumption that juries follow limiting instructions”).

^[17] Thomas J. Reed, Admitting the Accused's Criminal History: The Trouble with Rule 404(b), 78 Temp. L. Rev. 201, 212 (2005) (noting that “very few commentators believe that [limiting] instructions really curb the jury's common-sense use of uncharged misconduct”).

^[18] See Zafiro v. United States, 506 U.S. 534, 540–41 (1993) (reflecting that “juries are presumed to follow their instructions”).

^[19] See generally Capra & Richter, supra note 9.

^[20] See e.g. id. (proposing a “balancing test that admits the prior bad acts of criminal defendants only when their probative value outweighs any unfair prejudice to the defendant”); Advisory Comm. on Evidence Rules, supra note 8.

^[21] Gerald Gunther, Learned Hand: The Man and the Judge 549 (1994) (quoting Judge Learned Hand).