The Reactionary Mind by Cory Robin.
Robin's core argument is that conservatism's animating value is not freedom, small government, religion, or even an attachment to the past. Instead it's the belief in, and defense of hierarchy. He goes further to argue that Government and civic hierarchy is secondary to private and social systems. And the reason conservatives are so quick to defend hierarchy in institutions is the fear that liberation will leak into the private affairs of industry, society, and ultimately the home.
I'm suspicious of the thesis, but I have to admit, some of his ideas have worked like decoder rings for why MAGA acts the way it does.