In My Cousin Vinny, the impeachment is pretty much all about perception (eyesight, or perception of time, line of sight, etc.). Today we're going to concentrate on impeachment of the oath or ability to tell the truth.
But being a liar is a "pertinent trait of character" under 404(b). Of course, we needn't show that someone is a liar in general, but just that they might be telling untruths.
Character (404(a)(3)) is linked to 607, 608, and 609.
If you've called a witness, and you know there's impeaching information out there, you'll impeach them (in a friendly, explicative way) to blunt the opponent's side.
Note that this is really only a criminal case problem: in a civil case, the jury is instructed that they may draw an inference from the invocation of 5A. But we don't want to strike testimony in such a way that guilty people go free, so we allow the trial judge to deem certain questions "ancillary."
Well, 404 reminds us of Rule 408: character is relevant to the question of truth-telling.
So how do we do this? We might call to the stand a person who was wronged by the witness. We can't ask what the witness did to him/her. But we can ask "how do you know the witness?" "For how long?" "Based on that knowledge, do you have an opinion about his quality for truthfulness?" The opinion "he is a no-good lying son of a bitch" is admissible. We don't want the trial hijacked by questions about what the witness actually did that created the opinion. That's an efficiency issue, and also one of keeping focus on what the trial is about. The rules give us a compromise, then, when dealing with questions of credibility. We allow testimony about reputation, but not specific instances of conduct (except as provided in 608(b), 609).
Civil litigators need to understand this as well; maybe even more than criminal ones. When do you get to impeach someone by his refusal to testify on a claim of 5A privilege, and when not? In civil cases, even if you're not a trial lawyer, you might get asked questions when a client gets summoned to a deposition. So a deposition is the first setting where you'll have to worry about this.
In a deposition, it's proper to ask questions calculated to lead to the discovery of relevant evidence. So as long as the question is within those very broad bounds, it's proper to ask it, even if the answer incriminates the deponent. And one can't simply invoke 5A like you can in a criminal trial-- one has to invoke it on a question by question basis, not as a blanket like in a criminal case.
What about at trial, and there's a jury in the box? There's some variation by jurisdiction, but the majority rule is that it's improper to call a witness adversely solely for the purpose of forcing that witness to invoke the 5A privilege in front of the jury. So, if you think a hostile witness will take the 5th, the right thing to do is to ask the judge for a hearing out of the jury's presence, and go through the examination to see where, when, and how often the privilege is invoked. Then you can argue with the judge about how much of this you can present in front of the jury.
If, on the other hand, you're the cross-examining party (i.e., not the one who called the witness), if your questions are within the scope of the direct examination, and the witness now wishes to invoke 5A, the majority rule is that the question is proper, and the witness can be forced to invoke the privilege in front of the jury.
In a civil proceeding, the claiming of 5A allows an adverse inference: the jury is allowed to draw the conclusion that the witness' answer would have been unfavorable.
If cross-examination goes outside the scope of direct (this is not improper: impeachment, for example), the majority rule is that the jury should not hear the witness invoke the 5th. This is what we see, a little, in Zapata. Zapata's claim is that the 6A right of confrontation is infringed because the witness repeatedly took 5A. One of the reasons that the court says this is harmless is that the questions where 5A was claimed were outside the scope of direct.
So that's why the court doesn't strike all the testimony: you have the right to fully test whatever evidence was offered on direct (else the calling party would have an unfair advantage), but you don't have the right to introduce the a 5A issue that the opposing party wouldn't be able to ask about on redirect (and they wouldn't, because 5A was claimed).
Note that if a witness is testifying under immunity, the witness has no right to 5A any more, and can be forced to testify. (There's no such thing as immunity in the civil context, because only the sovereign can grant immunity).
Anyway, that's one of the rare-ish things about Zapata is that the defense lawyer's cross was so strong that the witness claimed 5A. This is much more likely to happen in civil cases.
Note that in order to testify, Mills has to establish that he knows Ehle (i.e., from prison), and that he's heard him talk about the lies. So that would impeach Ehle on the basis of bias: he's got a reason to lie (reduced sentence).
So the defense is introducing bias evidence against Ehle through Mills. That's 100% proper. Now the government recalls Ehle to show Mills's bias: he and Abel are members in Aryan Brotherhood, and membership in that organization requires that one lie, cheat, and so on, in support of one another. How does Mills know? Because he ALSO is a member, and therefore a fortiori it would have been suicide for me to tell Mills that I was going to rat on Abel.
Is this extrinsic evidence? Yes. Does that mean it's inadmissible? No, because it's relevant now that the issue has been raised and bias is never collateral.
What kind of thing would keep out relevant evidence of bias? Rule 403. That's always the last stop on the analytical choo-choo train of admissibility.
Is it prejudicial? Of course. Unfairly so? Well, the trial court didn't let the gang get named, because it's inflammatory: it has to be just called "a secret prison gang." What's important here is not the name of the gang, but its tenets. That's pretty sharp of the district judge, actually. This sort of instruction is quite common, it seems.