Rule 609.1 Evidence of bias, interest, or motive. (a) General rule. The credibility of a witness may be attacked by evidence of bias, interest, or motive.

(b) Extrinsic evidence of bias, interest, or motive. Extrinsic evidence of a witness' bias, interest, or motive is not admissible unless, on cross-examination, the matter is brought to the attention of the witness and the witness is afforded an opportunity to explain or deny the matter. [L 1980, c 164, pt of §1]

RULE 609.1 COMMENTARY

This rule has no federal counterpart, which means that common-law principles of bias, interest, or motive impeachment govern the practice in the federal courts. The problem is that the common law is divided on the question whether the impeaching material must, on cross-examination, be brought to the attention of the witness being impeached as a precondition to the proffer of extrinsic evidence. McCormick §40.

Rule 609.1 settles the issue and restates the rule of State v. Murphy, 59 H. 1, 17-18, 575 P.2d 448, 459-60 (1978):

The general rule is that a witness may be impeached through a showing of bias, hostility or prejudice, and this may be done by use of the witness' own testimony or by other evidence.... We believe that the correct rule is ... that before any bias of a witness can be introduced, a foundation must first be laid by cross-examining the witness regarding the facts which assertedly prove the bias. Two reasons are recognized ... for such a preliminary foundation. First, the foundational cross-examination gives the witness a fair opportunity to explain statements or equivocal facts which, standing alone, tend to show bias. Second, such cross-examination lends expediency to trials, for if the facts showing bias are admitted by the witness, the introduction of extrinsic evidence becomes unnecessary.

Case Notes

Admission of evidence of bias rests in the trial court's discretion. 67 H. 581, 698 P.2d 293 (1985).

Bias, interest, or motive is always relevant. 69 H. 204, 738 P.2d 812 (1987).

Trial court abused discretion by unconstitutionally excluding evidence of complainant's prior conviction, by prohibiting cross-examination of complainant, from which jury could have inferred that complainant had a motive to bring false charges against defendant and give false testimony at trial. 83 H. 109, 924 P.2d 1215 (1996).

Trial court was correct only insofar as it stated, by quoting this rule, that the credibility of a witness may be attacked by evidence of bias, interest, or motive, and that such evidence pertaining to a witness' credibility is always relevant and admissible at trial; trial court erred, however, in ruling that such evidence could be used by the jury in considering petitioners' motives as plaintiffs in filing the present lawsuit. 129 H. 313, 300 P.3d 579 (2013).

Where relevant evidence of witness' potential bias was elicited at trial, trial court properly balanced the prejudice concerns of defendant with the relevance and probative value of liability insurance evidence to reveal witness' potential bias; thus, trial court did not abuse its discretion in limiting evidence of bias, interest or motive with due regard for rule 403. 106 H. 298 (App.), 104 P.3d 336 (2004).