Q88. "Can a sitting President be convicted of a criminal offense? Or, must he be impeached first, then tried?"
A. There is no easy answer to the question, as it is a matter of interpretation. I think most Constitutional scholars would agree that the notion of separation of powers prevents the President, and perhaps the Vice President, from being prosecuted in criminal court while in office. So for a conviction, the President would have to either be removed from office, or the trial would have to wait until his term expired. Where there is less certainty is if a sitting President can be indicted while in office. In 1999, there were rumors that President Clinton might be indicted by Independent Council Kenneth Starr while Clinton was still in office, but this never came about.