There are many reasons the jury will dislike a witness - he lied to the police, he lied to investigators, he has a criminal history, he broke up a marriage in a divorce case, he doesn't pay child support, he got a plea deal in exchange for his testimony, or he lies on the witness stand.
The first question in a trial lawyer's mind should be, do I need to call this witness? Does this witness provide some material fact that we cannot otherwise get into evidence? If the answer is yes, then we move on to damage control.
Begin indoctrinating potential jurors early. If the witness lied to the police the night of the crime, tell them. If he's a five time felon, share it. If he smoked crack all day and is the only person that can identify the defendant, let them know. The key is to lay all our cards in front of them. Otherwise, it looks like we're hiding it.
Ask the jurors if they can still wait to hear the witness's testimony before making a credibility decision. If they cannot, then they will be excused. If they can, then we've successfully weeded out jurors who cannot be impartial on the case and took the sting out of the worst pieces of evidence.
We bring the negatives out through our questioning. This removes the "aha" moment during cross-examination when the defense attorney believes they caught the witness. Sandwich the bad information somewhere in the middle of the testimony.
I'll object to improper questions during cross and try to protect my witness. The defense attorney, however, will attack with everything he has on the issue. I don't mind though because I haven't hid anything. I tell every witness to be completely honest. If they are honest about all their dirty laundry, it is easy to use on summation.
There are so many ways to use a despised witness's testimony, that I must cut it down. First, I always explain that the DA's office doesn't pick the witnesses, the defendant does. If the jury doesn't like a witness, they can blame him for committing the crime in front of him. I'm not asking the jurors to become friends with the convicted rapist, just to believe his testimony.
Second, the detested witness boosts his own credibility. The defense attorney will spend so much time slamming the witness for lying to the police or being a crackhead that I get to use this on summation. "Mr. Smith sat in front of you on that witness stand and answered every question the defense attorney threw at him. Do you think it was comfortable to speak about all the mistakes he's made in his life? Do you think he enjoyed it? He was honest about his mistakes. Just like he is credible in his testimony that the defendant killed the victim. If he was lying or making it up, why wouldn't he lie about all the bad stuff he's done?
Third, when a cooperating witness gets a plea deal I get to argue that he's the defendant's friend. When a defense attorney attacks a cooperating defendant for his prior record or bad acts, I get to respond that this is the person the defendant associated himself with. These are his friends, not mine.
These are some ways to control and use an unlikeable witness. There are many other ways and many other arguments to be made.
Can anyone think of any other ways to use the witness? Where is your breaking point with a witness? What kind of bad things can't you overlook?