Obey was always a fluke of sorts. That area of WI can trend democratic, but it's generally "blue dog" Democrat (when that used to mean something) being largely socially and fiscally conservative Democrats, largely only liberal on labor and farm issues.
However, WI has a very "mushy middle" knee-jerk reactions to incumbents, and disassociates "the guy" from votes and policy which they may not like. And in the lower density rural districts, there's even more chances to get face to face with more of the electorate, and people get the vibe, shake hands, make eye-contact... "
Oh... he's a good guy.." and pull the lever for him, and not the party or the politics.
WI voters are really bad at understanding the power behind legislative majorities in terms of committee appointments, speaker positions, legislative gate-keeping etc. They tend to think very individually about the person and little else. I think it largely comes down to the fact Wisconsinites are above average at being nice laid back people, who don't get worked up over politics, and the pols with a "I'm just a guy.."-sthick ride it all the way into office. And the Democrats take advantage of that more.
That's also why we have Senators like Russ Feingold. His "aw shucks" campaign style and initial campaign where he had his policy points all printed out on his garage door played really well.
