Many scholars agree that once a president has been impeached, he or she loses the power to pardon anyone for criminal offenses connected to the articles of impeachment. Less noticed is that even after the Senate’s failure to convict the president, he or she does not regain this power.
Under Article II, Section II of the Constitution, the president is given the “power to grant reprieves and pardons for offences against the United States, except in cases of impeachment.” Pardons are supposed to be used as acts of mercy. The framers thought of the pardon power as a “benign prerogative”—prerogative because it was mostly unchecked by courts or Congress, but benign because presidents would use it for the public good.
But the framers knew not to place blind trust in the president to wield the power justly. That’s why they explicitly forbade a president from exercising the pardon power in “cases of impeachment.” The clause prevents the worst abuse of the pardon power: a president’s protecting cronies who have been convicted of crimes related to the president’s own wrongdoing.