How to Impeach a Trial Witness
Definition of “impeachment of a witness” from Black’s Law Library: “where the believability of a witness is questioned that is based on the testimony of other witnesses.”
Believability in a courtroom refers to whether a witness is speaking the truth. While most persons will be truthful, there are exceptions and if it can be proven by any party that the witness is not likely telling the truth, the witness will be impeached and their testimony will not be admissible in the court proceedings. The key word is “proven” and both the defense attorney and the prosecuting attorney have the right to examine, cross examine, and redirect questions to the witness whose testimony is in question. There are a number of areas where a person’s credibility can be in question, and if proven to be so, the witness is impeached. These areas include:
- Mental incapability to tell the truth as it was witnessed at the time of the incidence in question. If it can be proven the witness was under the influence of alcohol or drugs when witnessing the event it is highly unlikely the truth of the observation was accurately observed. Also, a history of serious physical or mental health problems can affect a person’s ability to be an accurate witness.
- A person could be biased against the accused and actually, hope the accused will be found guilty. Their testimony could then be untruthful in an attempt to discredit the person on trial, or, say a former friend, in the case of a family law matter such as a divorce. Often former co-workers, romantic partners, or disgruntled family members can carry a grudge over into the courtroom, making their testimony biased.
- If the witness has a criminal history of long standing it may be assumed their testimony will not be truthful. A conviction of a misdemeanor, such as shoplifting, a number of years ago would not count as a cause for impeachment if the action or similar small offenses have not been repeated. Juvenile convictions are not admissible for impeachment.
- Changing the story the witness tells on the stand when compared to former accounts but with different details can be considered a false testimony. This information can come from former oral statements put into writing. However, the witness must be given a chance to explain why the prior statement(s) differ from the courtroom testimony before an impeachment can be given.
- Other witnesses can prove that material facts stated by the witness to be impeached are not truthful. Again, “proof” is the key word here.
An experienced attorney will know to carefully check the background of witnesses he or she plans to use. In addition, the attorney should review with each witness all facts the witness will be questioned on to make sure the answers line up with the facts of the case in question. While it is true, opposing counsel may ask unexpected questions, if the witness is well acquainted with the facts in the case, his or her testimony will most likely be the truth.