Saying that Putin made him do it would make him look like a total wuss. He would stroke out before he cold utter the words.

but in this case, I think he is more afraid of Putin than he is Mueller.

not getting a needle in the arm. Treason is a capital crime, after all.

And honestly, he's so unreliable that his testimony is worth jack squat when it comes to generating useful new info the prosecutors would not already have.

Another problem: any plea deal involves the defendant's allocution. Trump is utterly incapable in engaging in a genuine allocution to a degree any self-respecting judge would find acceptable.