MBE Trap: Impeachment by Conviction of a Crime

It might seem, intuitively, that impeachment for convictions of felonies that have nothing to do with truthfulness would not be allowable. Impeachment, after all, is about calling into question the credibility of a witness, and it's questionable whether having been convicted of a felony that has nothing at all do with with dishonesty calls into question a witness's credibility.

But intuition doesn't guide here. All felonies (under the Federal rules) are admissible for this purpose. Misdemeanors, on the other hand, are only admissible to impeach if they are probative of dishonesty. The trap here is to not distinguish these types of crimes (and instead to lump them into one category: impeachment by conviction of crimes).

One commonality, though, is that both types of crimes can be proven by extrinsic evidence. That is, evidence outside of cross examination. The same rule above for misdemeanors applies for impeaching a witness on a prior bad act. A prior bad act is an act that does not result in a conviction but that is probative of truthfulness.

The difference here is that unlike with the misdemeanor rule above, impeaching on a prior bad act is only allowable on cross examination: extrinsic evidence is inadmissible.