The results from Michigan are in. Romney won his home state by a score of 41%-38% over Santorum.
It is a result that perfectly fits with the story of the primary campaign so far. Romney won, but he didn't win by much, and he didn't inspire much confidence (or anything else, for that matter) while he was at it. He'll likely march his way to the nomination, but it will take a good while, and if Santorum/Gingrich can get out of each other's way, they might still stop him.
Despite his failings, he is a better general election candidate than a primary candidate, given the ever-increasing conservativism in the GOP electorate. Romney's task has been to move far enough to the right to win the nomination without alienating the . While he seems to be more or less succeeding at the first part, he is miserably failing at the second.
Here (fair warning; look at the y-axis) a graph of Romney's favorability ratings over the past 2 years. Since the start of the year, his net favorability rating (% who view him favorably minus % who view him unfavorably) has moved from +8.3% to -13.1%. That's a big drop.
Much of this drop has to do with the tone of his campaign. Much of the ad spending during the primaries has been negative attacks launched by the Romney campaign and his Super PAC. With the cycling of temporary frontrunners, Romney has had to launch multiple rounds of attacks, leading to a perception that his campaign is mostly negative. Which it is.
If he wins in Ohio next week, he'll have much more freedom to talk more about his 59 point economic plan, or his plan to slash income tax rates by 20%. If he loses, he'll have to continue funding his attack machine, driving down his ratings even further.