My personal belief is that trial counsel should always raise claims, even that those that have no chance of success, as long as what is going on is even marginally unfair.
Today’s claim I’d like to discuss is vouching via admitting evidence that a cooperating witness has promised to the tell the truth. The California Supreme Court has held that this, alone, does not constitute vouching. (People v. Williams (2013) 56 Cal.4th 192.) Federal courts hold that this is permissible as long as the evidence is admitted only after the witness is impeached. (nited States v. Wallace (9th Cir. 1988) 848 F.2d 219, 223-224.) Under the Evidence Code in California, though, a prosecutor may seek to support a witness’s testimony before he is impeached. (Evid. Code § 785.) I would argue that federal law should control, but, in any event, there is still a way to make a vouching claim under California law.
Vouching, at its core, is both using the prestige of the prosecutor’s office to assure a jury that a witness is telling a truth but also to suggest that there is outside information the jury can rely on to determine that a witness is truthful. (People v. Fierro (1991) 1 Cal.4th 173, 211.) If it can be said that the prosecutor is eliciting evidence that suggests that the prosecutor, the court, or any other entity is going to evaluate whether the witness is telling the truth, then I think you have a valid vouching argument. I’ve seen proffer/plea agreements that say that the witness must tell the truth to get the benefit of a bargain and that a “neutral” judge will assess whether he did, in fact, tell the truth. In fact, I’ve seen an agreement that said that even after a neutral judge decides if he told the truth, the prosecutor will independently evaluate whether he told the truth before fulfilling the terms of the bargain. How this is not vouching is beyond me. Raise it.
I have briefed this. Email for a copy if you’re interested. email@example.com.