Impeachment

The MBE’s favorite trap is the collateral-matter bar: you can’t use extrinsic evidence to contradict a witness on a trivial point, so you’re stuck with the answer on cross—but bias is never collateral, so extrinsic proof always comes in (still subject to Rule 403). A close cousin is the prior inconsistent statement: to admit extrinsic evidence, the witness must get an opportunity to explain or deny it and the adverse party a chance to examine—Rule 613(b), now a sequential foundation as amended Dec. 1, 2024, unless the court orders otherwise (older banks may still call the timing flexible). Watch for a statement that both impeaches and proves the truth—only one made under penalty of perjury at a prior proceeding escapes hearsay under 801(d)(1)(A).

Don’t confuse impeachment with character evidence: untruthfulness attacks credibility (reputation/opinion under 608(a), specific acts only on cross under 608(b), no extrinsic proof), whereas 404 propensity proves conduct in conformity. And distinguish competency (the witness’s threshold capacity) from impeachment (attacking weight). Hook: “Bias is BIG, collateral is killed.”