Maybe not

In a post about "signing statements," Josh Marshall writes:

There's a body of literature and debate about this theory of the unitary executive.

But Elizabeth de la Vega, a former federal prosecutor with more than 20 years of experience, writes in Salon:

Not having heard of this concept, and thinking perhaps that I had missed something in constitutional law, I decided to survey a random sampling of attorneys about it. The group included civil practitioners, prosecutors, a federal judge, a former federal prosecutor who has a Ph.D. as well as a J.D., defense attorneys and a U.S. magistrate. The precise question was, "When did you first hear about the Unitary Executive Theory of the Presidency?" Most said, "The past few weeks," but my favorite was, "A few seconds ago, when you asked about it." All agreed that the term does not appear in the U.S. Constitution and that, the last time they checked, we still had three branches of government.