It has become a cliché to say that this election is not about electing a President, but preserving democracy in America. That’s much less because of Donald Trump than because of the “doom loops” (in Lee Drutman’s term) between the two political parties. It’s bad enough that we have only two parties that leave most of us poorly represented. But as the parties increasingly differentiate themselves across issues of identity and culture, the “winner-take-all” nature of our electora...