Which statement best distinguishes impeachment by bias from other forms of impeachment?

• A. It uses prior inconsistent statements to challenge credibility.
• B. It relies on expert testimony to prove lack of credibility.
• C. It focuses on personal or monetary interests that could affect truthfulness.
• D. It relies on the content of the testimony itself.

Answer: (C)

Impeachment by bias looks at the witness’s motive or interest that could color their truthfulness. The crucial point is that bias arises from a personal or financial stake or a relationship with a party that could cause the witness to lie or shade the truth. That makes their testimony less reliable because of the potential motive behind it.

The best choice captures this idea by focusing on personal or monetary interests that could affect truthfulness. In other words, it’s about external influence on the witness’s honesty, not about how accurate or inauthentic their statements might be in isolation.

Other options target different ideas. Using prior inconsistent statements checks whether the witness’s earlier words don’t match current statements, which is about consistency, not motive. Relying on expert testimony to prove lack of credibility isn’t a standard way to show bias. And relying on the content of the testimony itself focuses on what was said, not why the witness might be predisposed to lie.