Romney won 39% of the vote in the Michigan GOP primary in 2008. A poll out today of a hypothetical 2012 Michigan GOP primary shows that he has bled around 40% of his support from 2008:

Romney: 24.3%
Huckabee: 18.8%
Palin: 17.1%
Gingrich: 10.2%
Pawlenty: 3.5%
Santorum: 1.9%
Huntsman: 1.5%
Daniels: 1.0%
Barbour: 0.6%
Undecided: 21.0%

Keep in mind too that liberal Nate Silver found Michigan to be an incredibly below-average state for Governor Palin for the purposes of the GOP primary. However, she seems to be in a good position to potentially win this state or come close to winning it once Mike Huckabee announces that he’s staying on Fox News. Like New Jersey, Michigan is another state that Romney should win by a 15-20 point margin over Governor Palin but this poll suggests that he won’t come close to such a margin, if he wins at all, once Mike Huckabee is removed from polling.

No wonder some of Romney’s prominent 2008 supporters are bailing.