One contentious point in constitutional law is: to what extent do we have to conceive of the executive branch as unitary, as a single institutional expression of a single decider, the President? Or can there be legitimate fractures within that branch.
Many states have plural executives, such as those that allow for separate elections of the state attorney general. The AG, then, though clearly an executive figure, is not accountable to the governor. Now: the COTUS doesn't do anything like that. The cabinet serves at the pleasure of the President. So in some sense, the executive branch is unitary. But ... how unitary? There is a "weak unitary" theory advocated for example by Marty Lederman and David Barron, and as exemplified by Supreme Court decisions such as Morrison v. Olson.
At any rate, advocates of strong unity often take the position that the plain language of the COTUS supports their view. A fascinating recent article by Peter Shane contests that. Here's a link.
I discovered Shane's article with the assistance of the Legal History Blog.
Tug of the forelock to all the just mentioned people and institutions.