Beyond Sex Crimes: A Principled Approach to Admitting Evidence of Prior Bad Acts

Since the Federal Rules of Evidence were codified in 1975, few revisions have been as controversial as the rules allowing the use of prior “bad acts” of defendants in trials for sexually-based offenses. For nearly two centuries, such evidence had been banned under what we now know as Rule 404, which strictly prohibits “[e]vidence of other crimes, wrongs, or acts . . . to prove the character of a person in order to show action in conformity therewith.” But in 1995, Congress introduced Rules 413-415, which for the first time explicitly endorsed the use of prior acts of sexual assault and child molestation for the purpose of showing that the defendant, having committed such acts in the past, is more likely to have committed the crime in question. Although the rules are imperfect, they are here to stay, and more importantly, the next step for these rules may well be their expansion. Using the existing rules as a template for allowing character evidence in contexts beyond sex offenses will only exacerbate the rules’ current flaws, and therefore, the challenge facing federal rulemakers will be - not whether to repeal the rules entirely - but rather, how to expand these rules responsibly. That roadmap will be the subject of this Paper. The proposal offered here would require prosecutors desiring to use prior bad acts demonstrate, through the presentation of “qualified” and “compelling” research, that the defendant, having committed the particular prior acts, would be more likely to commit the crime in question. This presentation would occur prior to trial, typically through a Daubert-like motion or hearing, where expert testimony could be heard. On the one hand, this proposal would increase the burden on prosecutors to show that the particular prior acts should be admitted in the particular case - rather than relying on the existing categorical rules - but on the other hand, it would allow prosecutors to use character evidence in new ways so long as the burden is met. Courts would act as gatekeepers, and social science, rather than politics, will be allowed to guide the expansion in the use of propensity evidence.