§ 770 [Extrinsic Evidence of Inconsistent Statements]

When someone testifies in court and they said something different before, a lawyer might want to bring in outside proof of that earlier statement to show the witness is being inconsistent. This rule sets limits on when that outside proof can be used.

Before a lawyer can bring in that outside evidence, the witness usually needs a chance to address it first. This means either the witness was asked about the earlier statement while on the stand and given a chance to explain or deny it, or the witness is still available to testify again later so they can be asked about it then. If neither of these things happened, the outside evidence normally cannot be used.

There is an exception, though. A judge can allow the evidence anyway if fairness requires it, even if the witness never got that chance to respond. This gives judges some flexibility so the rule does not create an unfair result in unusual situations.