In 2001, Jeff Sessions, then a Republican senator from Alabama who is now Mr. Trump’s attorney general, voiced support for the idea of a bribery investigation into Bill Clinton’s pardon of Marc Rich, a fugitive financier whose former wife had donated to the Democratic Party and the Clinton library foundation.
In an Op-Ed published in The New York Times, two University of Chicago law professors, Daniel Hemel and Eric Posner, argued that if Mr. Trump pardoned his relatives and aides to cover up possible crimes and impede Mr. Mueller’s investigation, rather than for reasons of mercy or public welfare, it could increase the risk that Mr. Trump is later charged with obstruction of justice. Mr. Trump’s previous actions, including purportedly pressuring James B. Comey, then the director of the F.B.I., to back off the investigation into Mr. Flynn, have already raised that specter.
Could Trump pardon himself?
This is not clear. The only limitation explicitly stated in the Constitution is a ban on using a pardon to stop an impeachment proceeding in Congress, and the only obvious implicit limitation is that he cannot pardon offenses under state law.
But some legal scholars think a president cannot pardon himself, either, because it would be a conflict of interest.
In August 1974, four days before Mr. Nixon resigned, Mary C. Lawton, then the acting head of the Justice Department’s Office of Legal Counsel, issued a terse legal opinion stating that “it would seem” that Mr. Nixon could not pardon himself “under the fundamental rule that no one may be a judge in his own case.”
But she did not explain what transformed that principle into an unwritten legal limit on the power the Constitution bestows on presidents.
Other legal specialists have come out the other way. In a 1998 House Judiciary Committee hearing about the proposed impeachment of Mr. Clinton, for example, Representative Bob Goodlatte, a Virginia Republican who is now the chairman of that panel, stated, “The prevailing opinion is that the president can pardon himself.”