Why do the Dakota State Capitals Vote Republican?

[they don't love you like i love you]

For the record, there are relatively Democratic areas in Bismarck just south of the capitol where I'd imagine most of the state employees live. Obama won two precincts in Bismarck, one just south of the capitol grounds, the other south of that (which is the downtown area), McCain also didn't do that well in the surrounding areas, he got about 51% total in all those precincts, probably about 55% Romney victory. Still pretty strong, but not on the level of the county.

For Bismarck the name is actually a bit of a key. It's a heavily German as opposed to Scandinavian city, and was never an agricultural center, its economy aside from the state government has mostly been based around ranching, mineral extraction, oil refining, banking and health care. The state government employs about 4000 people, its the largest employer in the city, but the whole Bismarck metro now has over 100k people. Scandinavian agrian populism was never a thing there. And most of Bismarck's growth (which has been rapid since the 80s, long pre-oil boom) was from people moving there from economically unviable surrounding small towns, some of them German-speaking (though it's their kids now, the German speakers are mostly all in nursing homes), a very Republican demographic. Thanks to its isolation and how it developed Bismarck is also a city where churches were able to push a very socially conservative agenda that still has a lot of influence, the liberal ELCA associated with the Dakotas is actually fairly outnumbered by far more conservative Lutherans, the Catholic church and the Jesus Camp people combined. And it's an isolated low crime city where people outdoors recreation and hunting, there's guns everywhere and no one is really concerned about gun violence, attitudes toward guns there are more like what you'd find in a city 1/10 of its size. Both the demographics are culture are the sort of thing that would lead to being pretty conservative.

Also worth of note: Despite also being the second largest city in the state, Bismarck doesn't have a public state university. So kids from there go to school in either Fargo, Grand Forks or Minnesota. And the liberal ones are probably more likely to stay where they went (like me!)