We previously explored  the wonderfully amorphous evidentiary doctrine known as “impeachment by contradiction.” Sitting outside, but in parallel with, the Federal Rules of Evidence, the doctrine creates an exception to FRE 608(b) . The evidence rule generally limits a cross-examiner to matters relating to the truthfulness of a witness, together with certain criminal convictions under FRE 609 . However, under appropriate circumstances not spelled out in Rule 608(b), the doors to the courtroom are thrown open and a stream of otherwise extraneous matters can be brought to bear.

Once the witness’s direct testimony has opened that door, then nearly anything which contradicts the witness is fair game. The rationale for broadened cross-examination is to prevent witnesses from engaging in perjury, then using the shield of FRE 608(b) to preclude their successful impeachment with collateral facts.

A recent Eighth Circuit case which does not use the phrase “impeachment by contradiction” nevertheless well illustrates the animating principle. In United States v. Allen, 630 F.3d 762 (8th Cir. 2011), the defendant was charged with possession of an illegal machine gun. As part of its case-in-chief, the government had introduced a video of Allen showing his mother how to fire a machine gun. Presumably in an effort to make that demonstration appear more normal, Allen testified on direct examination that he was familiar with machine guns because of his military service. Had he stopped there, he would have been fine. Instead, Allen then testified that he was very proud of his military service and hoped to share his experiences with his children, and concluded his testimony by again mentioning his pride in his military service. In the view of the district court, this lily-gilding emphasis on the quality of his service allowed the government to cross-examine Allen about his arrests while in the military and his less-than-honorable discharge, neither of which meet the Rule’s criterion of matters going to truthfulness.

The Eighth Circuit found no abuse of discretion. Allen’s direct testimony opened the door to his being cross-examined on matters which contradicted that volunteered testimony, even if it would normally have been error to allow such impeachment otherwise.