Is illegally seized evidence admissible to attack a defendant’s credibility?
Illegally seized evidence is, for the most part, inadmissible in criminal trials. (See Fruit of the Poisonous Tree.) But there are exceptions. One has to do with “good faith.” Another involves credibility: What would be inadmissible evidence can sometimes come in at trial to impeach the testimony of a defendant who chose to testify. In that way, the government’s hands aren’t tied if it has evidence—albeit illegally obtained—that the defendant has lied on the witness stand. (This is the rule under the U.S. Constitution—states are free, though often unwilling, to make it tougher for the government to get illegally seized evidence into court.)