Comment by rayiner

The "unitary executive theory" is just a pejorative label for Article II, Section 1, Clause 1: "The executive Power shall be vested in a President of the United States of America." Alexander Hamilton talks about it in Federalist 70: "I rarely met with an intelligent man from any of the States, who did not admit, as the result of experience, that the UNITY of the executive of this State was one of the best of the distinguishing features of our constitution." (https://avalon.law.yale.edu/18th_century/fed70.asp).

Nobody called it a "theory" until FDR appointees ginned up a fourth branch of government in the 20th century. Then, they needed a label for what actually existed in the constitution to distinguish it from the shit they just made up. But most of the people who use the phrase "unitary executive theory" also think "emanations from penumbras" is constitutional law...

Also, the APA doesn't apply to the President, and it wouldn't be constitutional for it to do so.