In 2008, Obama carried Wisconsin by 14 points. Here was his breakdown by county:
The election was closer this year against Romney, however Obama was still able to pull out a win. Obama lost 23 counties to Romney that he held 2008 (according to my count).
Romney did take the rural vote, however it wasn’t enough to bring him over Obama. One key county turnover that I see from 2008 is Brown County. Brown County is where Green Bay Wisconsin is located. Green Bay is the third largest city in Wisconsin, which gave Romney a lot of votes there.
But Obama held onto Milwaukee’s county and Madison’s county, the two largest cities in the state, which ultimately gave him the win of the popular vote in the state.