Propensity—Persuasion and Prejudice

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“He did it before, do you really think he didn’t do it this time?”

This is the stuff of a defense lawyer’s nightmares. Lawyers lose sleep over the notion that, despite all their hard work defending the specific charges in a case, their client’s prior sins will nevertheless be admitted into evidence and take on outsize importance in shaping the jury’s impressions of the client. And for good reason. Evidence of a person’s propensity to act in a certain way can be utterly devastating. Jurors may focus unduly on the prior acts of misconduct to the exclusion of the government’s heavy burden of proof, and they may be more willing to accept other evidence offered against the defendant because it makes more sense, given that, in their minds, the defendant is a bad actor.