Right wing Ralphie wrote:
Is Trump seriously taking the witness stand tomorrow?
he can’t speak without lying. not even one sentence. Do his attorneys hate him?
Keep in mind that President Trump may have been the one who insisted on his testifying. Many possibilities for fundraising off that, particularly if he can deliver a pithy line or two.
Ultimately, you work for your client. If you think s/he's likely to lie, you can withdraw from representing the individual...but that can cause its own problems for a lawyer.