According to a recent article in the National review, Romney would be extremely foolish to drop out of the race, even if he loses Michigan.
This will probably not be a momentum-based campaign. If all the Republican candidates held roughly similar views (as with this year’s Dems), then a Romney loss in Michigan might be decisive. But in the Republican race, Romney holds a place (fairly mainstream conservative across the board) matched by no other candidate. Given the resistance of some portion of the conservative base to every other candidate, Romney would be foolish to drop out, even after a loss in Michigan. In fact, Romney stands to capitalize on what may well be the next big development in the race, the (relative) rise of Giuliani, at McCain’s expense.
I think that Romney should stay in this thing until a clear frontrunner emerges.
Another thought as to why Romney may just win in Michigan: Michigan will be the first state where Huckabee and McCain will both have a dog in the fight. The moderate Republicans will be split between McCain and Huckabee. The anti-mormon vote will be split as well. The religious voters for Huck, the moderate and trendy (less informed) votes to McCain. Romney will gather the more traditional Hannity/Rush Limbaugh Republicans.
Even though McCain and Huck will have a combined score better than Romney's, Mitt could still come out with the win. So, a possible outcome could be Huck 23, McCain 27, Romney 29. A Romney gold medal! John McCain is probably on the phone with Huckabee right now asking him to lay low in Michigan so that he can be the moderate's alternative to Romney. But will Huck take the bait? Two wins in a row from the Macster could really threaten Huck's chances. Huck better have a good showing in Michigan or else he may be out...a one hit wonder!
What about the Democratic spoilers? You know, those folks who will vote for a moderate (they themselves being dems) to try to disrupt a conservative nomination? They will also be split between McCain and Huckabee. And they won't be as organized as they were in New Hampshire. Michigan is a lot bigger state...with millions more in residents. If you are a spoiler who do you go for Huck or McCain?
In a few days, we will see what happens...but either way Romney will probably still lead in delegates and total votes...leaving Romney little reason to drop out.