The old populism was strong in the middle of the country at the end of the 19th century and well into the 20th. I reckon I need to educate myself about it more fully if I want to talk about it at any length. In the mean time, though, check out
about the recent article in Harper's by Thomas Frank, author of the forthcoming What's The Matter With Kansas? (the state being, he argues, a microcosm of the whole U.S. of A.).
The article has some good links, including one to the 1896 essay of Wm Allen White from which Frank's book takes its title.