The version of the “unitary executive” put forth by Mr. Trump, the Justice Department and the shareholders would open the door for a president to fire for any reason — even personal reasons unrelated to the public interest or even for no reason at all — any head of an administrative agency, including the heads of “independent agencies” like the Consumer Financial Protection Bureau as well as the Federal Reserve, the Federal Trade Commission and the Nuclear Regulatory Commission. (These agency heads are nominated by the president and confirmed by the Senate.)