Also known as: impeach witnesses · impeaching witnesses · impeached witness · witness impeachment · impeachment
Written by attorneys · grounded in primary & secondary sources — see below
A method of challenging the credibility of a witness through cross-examination or extrinsic evidence. It includes attacks based on bias, prior inconsistent statements, prior convictions, or contradiction with other proof.
Isla Ireland sued Imperial Motors after a workplace injury. Imperial Motors identified a coworker only days before trial to testify that Isla had previously complained of similar symptoms from a different cause. Because the coworker would be used solely to impeach Isla's testimony about the origin of her injuries, Imperial Motors was not required to list the coworker in its initial disclosures.
Imani Idowu claimed that Island Manufacturing's conveyor belt lacked adequate guards. After her injury the company installed additional guards. At trial Imani sought to introduce the installation to show the original design was defective. The court excluded the evidence for that purpose but permitted it to impeach a defense expert who had testified that extra guards were unnecessary.
Select any source to read its text and confirm it supports the definition.
Ibrahim Iqbal, a former agency official, testified before a Senate committee investigating executive misconduct. When the full Senate later tried the matter, the committee record was offered to impeach Iqbal's live testimony. The record was admitted for that limited credibility purpose.
Irene Ingalls sued Infinity Bank for wrongful termination. During initial disclosures the bank produced internal emails but omitted a memo that would contradict its HR director's expected testimony. Because the memo would be used only to impeach the director, the bank was not required to produce it with the initial document disclosures.
Ismael Ibrahim was convicted of perjury after testifying falsely at a federal trial. The President considered granting a pardon. The conviction was used to impeach Ibrahim in later proceedings because the pardon exception did not apply.
Ines Ibarra was called as a defense witness in a criminal case. The prosecution sought to impeach her with a prior inconsistent statement recorded in a state-court transcript. The federal court admitted the transcript for impeachment under its authority over cases arising under federal law.
Common methods include showing bias or motive, prior inconsistent statements, prior convictions involving dishonesty, and contradiction with other evidence. Extrinsic evidence is permitted for some attacks but not others.
Supporting sources
Initial disclosure rules exempt individuals whose information will be used solely for impeachment. The same exception applies to documents produced only for impeachment purposes.
Evidence of subsequent remedial measures is generally inadmissible to prove negligence or defect but may be admitted when offered for impeachment or to prove ownership, control, or feasibility of precautionary measures.
…and a showing the declarations were in furtherance of the conspiracy. Recorded conversations may additionally be admissible for impeachment of witnesses who testify. Given the potential evidentiary uses of the material and the time required for analysis and transcription, the District Court did not err in authorizing the subpoena duces…