I'll definitely give it a look. Whether we use the normal theory or politicians decide to intervene, I think you captured the issue.

Cohen's issue with LBJ is not really that he meddled, but that he meddled badly.
That pertains to both military and civilian leadership, competence matters. I also think depending on the nature of the conflict or perhaps what phase we're in, one can shift between a normal theory heavy approach or a politician meddling approach.

And the old line about military professionals being like surgeons who rarely if ever perform surgery has some truth to it.
It has a lot of truth to it, and the implications go further than meets the eye. We rely heavily on history (Sun Tzu, Clausewitz, Jomini, Mao, etc.), which of course has merit, but the world moves on politically, culturally, and perhaps most importantly technologically, all of which provide a new context that a savvy political leader is probably more aware of than an officer who views the world through a doctrine that could be outdated. Just a thought.