The 5th Amendment is a protection against self-incrimination. You can’t be forced to give evidence (not verbal evidence anyway) that can be used against you at trial. However, if there is no possibility of prosecuting you based on your testimony, then there is nothing for the Fifth Amendment to protect and therefore it cannot be invoked. If you received an immunity deal from the prosecutor in return for testimony, if you have already been convicted or acquitted of the crime about which you are testifying, or if you have been pardoned for either a specific crime for which you have been tried, or for any crime relating to a series of events in question, then you cannot be prosecuted, and therefore you cannot avoid testifying. So, the only situation in which you still have Fifth Amendment protections after a pardon is when the pardon is for a specific crime, and you know that your testimony could produce evidence against you that could lead to a prosecutor charging you with a different crime. In addition, the different crime cannot be an escalation of any crime for which you have been tried; double jeopardy prohibitions prevent charging you again with murder if you’ve already been tried for manslaughter in the death of the same person. So, for instance, let’s say you found yourself facing obstruction of justice charges for misleading a Federal investigation. You then received a pardon for said charges. You could, theoretically, still take the Fifth to avoid testifying as to the events that you had originally been obstructing, because if you were never charged with a crime for those events, you still can be, and your testimony could be used as evidence to further those charges. The pardon you would have to receive would have to be wider in scope, absolving you of any culpability for any crime regarding the actions being investigated. https://www.quora.com/If-a-person-r...till-have-to-testify-within-the-5th-amendment Remember the Perjury charge that Lucy's Vanity Fair link referred to? Or if he thinks he could be brought up on Obstruction charges or anything else, let alone what he could face in a State Court, where Trump's pardon will do him no good at all. I do not believe that Manafort's Right to Silence has been forfeited, that only applies to the charges for which he was found guilty: bank fraud, tax fraud and failure to report a foreign bank account. Yeah sure, Manafort's Right to Silence is gone for these charges, but so what? That ain't what they're going to be going after Trump for, now is it? If Trump and/or Manafort is also guilty or even possibly guilty of Obstruction and whatever else Mueller can dig up, then Manafort certainly has every right to plead the 5th. Why? Because his testimony could produce evidence against himself that could lead to a prosecutor charging him with a different crime. A Trump pardon does not change that fact.