Why is Iowa so Democratic?

[Verily]

A better question would be why is Iowa not uber-GOP considering it has no very large cities or many minorites. The whole upper Mississippi is pretty friendly to the Dems.

Vermont would like a word with you.

Anyway, Iowa does have cities. They're not big enough to have experienced urban decay, so they don't have substantial minorities or suburban white flight. They are, however, big enough to feel metropolitan, especially to people who grew up on farms, and that makes them quite Democratic.