Conservatives are eager to blame Detroit’s problems hazily on “Democrats,” and in most respects I think that’s wildly misleading. But I do think there’s an important sense in which they’re correct. American cities across the board suffer from a lack of partisan competition that undermines democratic accountability.
My view of this is heavily based on the work of George Mason University’s David Schleicher, and I really encourage you to look at his research for a long version of the story. But the short version is that ordinary voters rely heavily on party affiliation as a heuristic when deciding who to vote for. If you move to a new place with same-day voter registration, then pay zero attention to local politics up to and including the names of your local member of Congress, then show up at the voting booth to vote in a House election you’re in fact perfectly capable of making a well-informed decision about who to vote for. If you generally like legal abortions, equal rights for gays and lesbians, higher taxes, and more regulation of private businesses then you should vote for the Democrat. If you want tax cuts, abortion bans, and lax regulatory enforcement then you should vote for the Republican. You may have a hard time making up your mind because you feel cross-pressured (say you love tax hikes and abortion bans) but it’s easy to know what politicians stand for even without knowing anything about them. In fact, thanks to things like the Hastert Rule it actually barely matters whether the specific individual you’re voting for is totally orthodox or not. Partisanship makes life easy.
Shift to a big city, though, and you have a mess on your hands.