Witness impeachment
Witness impeachment, in the law of evidence of the United States, is the process of calling into question the credibility of an individual testifying in a trial. The Federal Rules of Evidence contain the rules governing impeachment in US federal courts.
Methods[edit]
In the US, a party has the option of discrediting a witness through impeachment by cross-examining the witness about facts that reflect poorly on the witness's credibility or, in some cases, by introducing extrinsic evidence that reflects negatively on the witness's truthfulness or knowledge.
In Pennsylvania, the procedure for determining whether a testifying defendant may be impeached is known as a Bighum hearing.[2]
Bolstering and rehabilitating[edit]
The general rule is that the proponent of a witness may not attempt to build up the witness's credibility prior to being impeached. The rationale is that the witness is presumed trustworthy. It also speeds proceedings by not spending time bolstering when the other side may not even impeach the witness.
To rehabilitate a witness, the proponent is confined to using the same techniques used by the opponent to impeach the witness. That is, if the opponent impeached via bias, rehabilitation is limited to negating the claim of bias. If the opponent brought in a rebuttal witness who testified to the character of principal witness as that of a liar, rehabilitation is limited to a character witness who testifies principal witness is a truthful person. That is a different consideration from the ever-present right to cross-examine any witness, including character witnesses.
If the opponent shows that the witness made a prior inconsistent statement and implies that after that statement and prior to trial the witness was "gotten to" or otherwise developed a motive to lie in court, rehabilitation can be attempted by showing that the witness made a prior consistent statement (consistent with the testimony) before the alleged events that gave rise to the alleged motive to lie. The jury is left with two pretrial statements that are inconsistent with each other, but only one is inconsistent with the testimony, and both were made before the witness was allegedly gotten to. Thus, there might be softening of the accusation that the testimony flows from such as a bribe. Also, there is always a case for allowing a prior consistent statement made at any time before trial to help explain away what is arguably only a seemingly inconsistent statement that is subject to interpretation, such as if it was lifted out of the context that would explain the statement.
External links[edit]
Media related to Impeachment in the United States at Wikimedia Commons