While the president’s pardon power is absolute, most legal scholars argue that a president cannot pardon himself. On August 5, 1974, acting Assistant Attorney General Mary Lawton wrote a memorandum with regard to the possible conviction of Richard Nixon that a president could not pardon himself. Admittedly, this is only a Justice Department opinion. It is also clear that the president cannot pardon himself for being impeached and removed from office, which may well be a non-issue if he were reelected with a closely divided and highly partisan Congress.
Another possible workaround if Ms. Lawton is, in fact, deemed correct is that a president who has been indicted and convicted could step down and allow the vice president to take over his responsibilities under the 25th amendment under the theory he was temporarily unable to perform his duties. The vice president, now being the acting president, could exert the presidential pardon power to pardon his predecessor. Congress also has the power to pardon a president who has been convicted for a federal offense. However, this possibility is likely remote in the current political environment.
More fundamentally, a president’s pardon powers extend only to federal offenses. States can still prosecute and imprison a president for violation of state criminal law. There are limits.