Character Evidence Rules

Federal Rule of Evidence 404 establishes the general prohibition against character evidence: evidence of a person's character or character trait is not admissible to prove that on a particular occasion the person acted in accordance with that character or trait. This rule rests on the policy judgment that character evidence is marginally relevant but highly prejudicial — jurors may convict a defendant not for what they did but for who they are.

The prohibition applies to character evidence offered for the propensity inference: using evidence that a person has a particular character trait (such as being violent or dishonest) to suggest they acted consistently with that trait on the occasion in question. Rule 404(b) codifies this limitation for evidence of other crimes, wrongs, or acts, but provides a critical exception: such evidence is admissible for non-propensity purposes, including proving motive, opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident. The admissibility of 404(b) evidence is one of the most litigated issues in criminal law.

Important exceptions to the general prohibition exist in criminal cases. Under Rule 404(a)(2), the accused may offer evidence of their own pertinent character trait (e.g., peacefulness in an assault case), and if they do, the prosecution may offer evidence to rebut it. The accused may also offer evidence of the victim's pertinent character trait (e.g., violence, to support a self-defense claim). Rules 413-415 create broad exceptions for sexual assault and child molestation cases, allowing the prosecution to introduce evidence of the defendant's prior sexual offenses to show propensity.

Character evidence may be proved by three methods depending on context: reputation testimony, opinion testimony, and specific instances of conduct. On direct examination of a character witness, only reputation and opinion evidence are permitted (Rule 405(a)). Specific instances of conduct are permitted on cross-examination of a character witness and when character is an essential element of a charge, claim, or defense (Rule 405(b)).