Even if there were clemency for Manafort, it may not keep him from talking. We also asked Bill Thomas, another attorney and former federal prosecutor, about the effect of a possible pardon, and he said it wouldn't do anything to stop Manafort from testifying. Quite the opposite.

"It seems to me that a pardon would have little effect on the investigation other than to reduce Manafort's willingness to cooperate," he told Law&Crime in an email. "A pardon may take the case out of the federal criminal arena as it relates to a conviction and punishment, it does not however relieve one of the obligation to be a witness if he were subpoenaed to the grand jury or at trial. He would still be obligated to give testimony. This is particularly true since under the scenario you posed -- a hypothetical pardon --- he would have no criminal liability (given that he has already been tried and convicted) and likely no ability to meaningfully assert the 5th Amendment."