Indiana is more Pub than the rest of the zone because it is more culturally traditional, it is "in" to be young and a Christian, it's light on the ground with upper middle class liberals, and the base of the Dem support there is white working class folks who have been trending Pub as the private sector unions died. And the Indianapolis Star is still a conservative rag so far as I know, unlike most big city papers. It also doesn't have many Hispanics of course, but yes that is true of the region in general outside of Chicago. It also has less of a Yankee cultural population than say Michigan, Wisconsin, and Ohio and Illinois (Protestants from New England), which population has trended to the Dems. Just my guess at it.
I recently drove through Indiana, and I think it gave me a pretty good feel for the state's politics. You can see that there's a lot of farm country, which we all know is pretty decisively Republican (despite its absolute dependence on government subsidy). But once you get to the suburbs of Indianapolis, you get a different feeling. The area is much more modern. People congregate at Starbucks. People own iPads. They're Republicans, a lot of them, but they're living in the 21st century.
That's why Donnelly won. These voters took a look at Mourdock, and didn't see themselves. They saw some bizarre caricature of the worst of the Republican Party. They saw someone who, while pro-life like them, took his beliefs to a hateful extreme that made it sound like he was blaming women for their own rapes. They saw a man who, in the primary, said that it was his duty to inflict his beliefs -- these ugly, reprehensible beliefs -- on others.
Romney isn't that kind of Republican. It's hard to know what Romney truly believes (and personally, I think his position on social issues has a very unfortunate super-conservative Mormon taint to it), but it's easy to separate Romney from Mourdock. That's why Romney won. Voting for Mourdock requires a very specific ability to rationalize brutally out-of-step, countercultural behavior. And in the end, that's all the votes he got: Some from hyperpartisans who were willing to look past clear faults to win a GOP Senate, and some from tea party true believers who think it was a mistake giving women the right to vote. That's just not a winning coalition in Indiana or Missouri.
