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When Character Evidence Can and Can’t be Used in a Federal Criminal Prosecution


When is it OK to defend yourself against a federal criminal charge using evidence of your good character? When is it OK to use character evidence against your accuser? The Federal Rules of Evidence strictly limit the use of character evidence. There are exceptions, however, as well as loopholes that sneaky prosecutors can slip through.

What Is “Character” Anyway?

Although there is no formal legal definition of “character,” in practice, courts have treated it as any pattern of behavior and is not limited to morally significant behavior – shyness or fastidiousness, for example. It is not the same as reputation, although it is related. Character is also not habit; character is thought to be deeper than habit.

Rule 404

Rule 404 of the Federal Rules of Evidence establishes a general prohibition against character evidence, subject to certain exceptions:

  • The defendant may introduce evidence of his own good character, even to the point of calling character witnesses.
  • The defendant may introduce evidence of the accuser’s bad character, subject to certain exceptions.
  • In a homicide case, if the defendant asserts that the victim was the aggressor in the encounter that provoked the homicide, the prosecutor may introduce character evidence (about the accuser’s character, not the defendant’s character) to rebut the defendant’s assertion.

The Mercy Rule

The “mercy rule” allows the defendant to introduce evidence of his own good character, as stated above. It can easily operate as a trap. Once the defendant introduces evidence of his own good character, the prosecutor becomes entitled to rebut the defendant by introducing evidence of his bad character. For this reason, criminal defense attorneys are reluctant to invoke the mercy rule.

Types of Character Evidence

The defendant may call witnesses to establish good character in the form of:

  • His reputation in his community;
  • The witnesses’ personal opinion of his character; and
  • The witnesses’ recounting of specific acts performed by the defendant (that are within his personal knowledge).

The Prosecution’s Rebuttal during Cross-Examination

The prosecutor can do great damage to the defendant’s standing with the jury by using the defendant’s own character witnesses against him during cross-examination. For example:

Witness: “Paul is an honest person. I’ve never known him to steal anything from anybody.”

Prosecutor: “Would your opinion change if it were proven that the defendant was arrested for shoplifting in 2007 and again in 2013?”

At this point, it doesn’t matter if the witness doesn’t change his mind. The jury now knows of the two previous convictions and will likely hold it against the defendant. Note that the prosecutor could not ask the witness about the defendant’s previous conviction for disorderly conduct, since that is not a crime of dishonesty.

The Relevance Loophole (and Limitation)

One of the ways a prosecutor can slip in character evidence against the defendant, in the absence of a formal exception, is to establish its relevance to a matter other than the defendant’s character. A prosecutor might, for example, seek to introduce evidence of past crimes committed by the defendant as a way of establishing that his “M.O.” was similar to the crime at issue.

The relevance loophole is limited by the facts of the case. If the defendant is accused of embezzlement, the prosecutor cannot introduce evidence of the defendant’s violent past, even if the defendant calls character witnesses. This is because violence is not relevant to embezzlement. The prosecutor cannot attempt to prove that the defendant is a “generally bad person” – he must be specific.

Affirmative Defenses

Certain affirmative defenses can open the door for a prosecutor to introduce character evidence. For example, in an entrapment defense (where the defendant argues that the police encouraged him to commit the crime so they could arrest him for it) the prosecutor is entitled to prove, through past bad acts, that the defendant was already predisposed to commit the crime.

Likewise, a defense of Not Guilty by Reason of Insanity invites the prosecutor to try to prove that the defendant is evil or degenerate rather than insane. Depending on the number of skeletons in the defendant’s closet, this could devastate the defendant’s standing in the eyes of the jury.

Character of the Accuser

The defendant is entitled to try to prove the bad character of the accuser in a manner relevant to the case. Except in certain homicide cases, however, this entitles the prosecutor to introduce both (i) evidence of the accuser’s good character in the same trait and (ii) evidence of the defendant’s bad character in the same trait.

If the defendant asserted that “It was the accuser who started the fight, not me” and then introduced evidence of the accusers violent tendencies, the prosecutor can respond by (i) introducing evidence of the accuser’s peaceful tendencies and (ii) introducing evidence of the defendant’s violent tendencies.

The Federal “Rape Shield” Rule

An exception, known as the “rape shield rule,” prevents the defendant from trying to prove the bad character of the defendant when the defendant is accused of sexual misconduct and the defense wishes to prove that the accuser was sexually promiscuous.

Several exceptions exist to this rule, however. Moreover, the rape shield rule would not prevent the defendant from trying to attack the accuser’s credibility on the witness stand by proving that the accuser is dishonest.


By swearing to tell “the truth, the whole truth, and anything but the truth,” every witness automatically places his credibility at issue, regardless of whether the witness is the accuser. For this reason, either side may try to prove that the witnesses’ testimony is not to be trusted, as long as the proof itself is relevant to credibility.

Don’t Let Passivity and Procrastination Determine Your Fate

A federal criminal prosecution is serious business. U.S. criminal law is based on an adversarial system, and that means the prosecutor is not your friend. Make no mistake about it, a criminal prosecution is a war, whether it takes place in open court or during plea bargaining. Hacker Murphy can help you fight that war with every weapon in our legal arsenal.

If you have been arrested for or charged with a federal crime in Schenectady, NY, or if the police have questioned you, you need to speak with an experienced Schenectady criminal attorney right away. Contact us today for a free initial consultation by phone, at our Schenectady office on Airport Park Boulevard, or even in jail. Act quickly – you have no time to lose.