In the Lower Peninsula, the counties that went for Romney in a big way generally went for Obama in a
UPDATE: Commenter CSH at Johnathon Bernstein's blog remarked, "I can't recall seeing the rich-poor, East-West gap in that state as strongly represented as last night." CSH also pointed out that Romney won the State by 32,000 votes. Coincidentally, he won Oakland County by 32,000 votes. The rest of the State was a wash.
The Upper Peninsula as always, has its own different story. Santorum carried all but two counties, and generally by large margins, while the the '08 vote was split among counties between Obama and McCain. The primary was closest in the eastern section of the U.P., which McCain carried in '08. But vote counts in the U.P. on Tuesday were very sparse - in the range of a few hundred to about 3,000 total, per county.
It's far from one-to-one, but Romney's results vs Santorum more or less parallel Obama's results vs. McCain four years ago. Romney's best showings were in places where he has virtually no chance in the general election. Santorum's best showings were in less populated areas that are likely to vote Republican, regardless.
The other significant factor is voter turnout. Romney and Santorum together collected 787,420 votes, Statewide. In 2008, McCain got over
Despite the hype, the stark differences between the two front runners, and Romney's alleged home field advantage, the total turnout was less than half of McCain's votes in '08 this looks