wow, never knew Detroit was just an abandoned factory.
btw, Detroit began it's decline in the 1950s. It's mayor then, Albert Cobo, was Republican, as was his successor, Louis Miriani.
Albert Cobo started a massive highway building program which destroyed huge swaths of the city and siphoned the better off to the suburbs, as well a large part of production. The better off tended to be 'Whites,' who were the ones usually promoted to better positions.
The less well-off lived in houses clustered round factories during the boom, which was fine when they moved there from southern states. With house values declining, and no one wanting to buy them anyways, those people were stuck. Public transportation was lacking, so they couldn't even make it to the outside areas jobs were relocating to. Business (stores, food, etc) that catered to workers thus also went down.
Later Republican policies on the federal level lured car makers and other manufacturing to the South with its lower wages and tons of unemployed to hire, thus furthering the decline.
Oh, the current Downtown Detroit revival? Guess who's responsible for that.