On 4 June 2018, President Trump, amid increasing public scrutiny stemming from Special Counsel Robert Mueller’s investigation, tweeted that he had the full and complete authority to pardon himself if he saw fit to do so.

The claim that a president has the absolute power to pardon himself has been made with respect to past presidents as well. Indeed, numerous scholars have argued that such an action would likely be constitutional, as the power to pardon is exceptionally broad — by design. 

The reason for this uncertainty is twofold. No president has ever attempted to test the legality of a self-pardon; furthermore, with only a few dozen people in the history of the United States having ever held the power of the pardon, there is limited casework to guide scholars and lawyers.