Levinson & Pildes, to the extreme

Daryl Levinson & Richard Pildes' Separation of Parties, Not Powers argued that the basic component and theory of separation of powers--competition and cooperation between the branches--ebbs and flows depending on whether one party controls both branches. They published the piece in 2006, covering periods through W.'s first term, when the push-and-pull was over policy and perhaps some political use of legislative oversight.

The current crisis (and yes, it is a crisis) takes their thesis to the extreme. It is not just that a Republican Congress does not push back on a Republican President's policy goals and actions; that follows from shared policy preferences. This is a Republican Congress not pushing back on a Republican President's efforts to neuter Congress and to place all power in the executive. It shows that, even in the extreme, political partisanship defeats separation of powers--party loyalties and prerogatives prevail over branch loyalties and prerogatives.