When can evidence impeach a witness?

Evidence can impeach a witness when it specifically attacks the witness's truthfulness or accuracy. The primary purpose of impeachment is to challenge the credibility of a witness by highlighting inconsistencies, biases, or motives to lie. This can include evidence such as prior dishonest conduct, specific instances of untruthfulness, or a demonstrated lack of accuracy in their testimony. By focusing on the witness's character for truthfulness or reliability, the impeachment process seeks to cast doubt on the validity of their statements and the overall quality of their evidence in the case.

While a criminal history may have potential implications for credibility, it is not automatically sufficient for impeachment without additional context or ruling on its relevance. Corroboration by other witnesses typically serves to strengthen a witness's testimony rather than impeach it. Lastly, references to previous statements can support or undermine testimony, but they do not inherently serve the function of impeachment unless they directly indicate inconsistency or deceit. Therefore, the emphasis on attacking truthfulness or accuracy is the most direct and applicable answer regarding when evidence can impeach a witness.