>smear
Very effective, many on the left will never believe anything Assange says after this. There will always be doubt as to the validity of his testimony, regardless of what he says.
>contingent on him denying Russia stole emails
If the plan was to bring him back to the US as a witness, they should have gotten in front of this one and said it was contingent on Assange telling the truth about where he got the emails from.