It is not hard to figure out what state is the highest priority right now for Mitt Romney, as he heads Thursday to Michigan for several days of campaigning, trying to prevent what would be an embarrassing defeat in the state where his father was once the Governor.

Romney goes to a Tea Party event in Milford on Thursday evening, almost halfway from Detroit to the state capital of Lansing evening; then on Friday he presents a major economic plan to the Detroit Economic Club.

Romney's latest trip to the Wolverine State comes as polls are split on what's happening in Michigan, though it seems clear that Romney has picked up momentum in the past week, thanks in part to an ad blitz that is slamming Rick Santorum.

Michigan might be more of a "must win" for Romney than Santorum, who seems likely to blame any loss on a tide of money from Romney and outside groups supporting the former Massachusetts Governor.

"Mitt Romney's negative DC attack machine has spent millions of dollars in false, negative attack ads against Rick Santorum for weeks now," trumpeted a Santorum news release yesterday, as the Santorum camp noted a Rasmussen poll showing him leading Romney by four points in Michigan.

"This poll is of note given the millions of negative advertising Governor Romney and his Super PAC supporters have invested in Michigan over the past two weeks to tear down Senator Santorum," the release read.

Political experts in Washington, D.C. are starting to wonder a bit about Romney and his campaign, especially after figures emerged this week showing that Romney spent almost three times as much money in January as he raised.

"For Romney if it weren't for his personal wealth, I think he would be in very serious trouble right now," said Norm Ornstein of the American Enterprise Institute.

Ornstein says if Romney doesn't do well in Michigan and then on Super Tuesday, there could be broader issues with raising big donations.

"That money will begin to dry up and he will have to turn to his own financial wealth," Ornstein added at an election symposium this week.

For all of Romney's fund raising prowess, he is the worst in the GOP field when it comes to small donations.

When you look at the calendar, it isn't hard to imagine Romney losing a number of contests over the next four weeks.

One poll of note came from Oklahoma on Wednesday, which showed Santorum with a 21 point lead over Newt Gingrich, with Romney in third.

That is the worst nightmare for Romney in coming weeks, as Oklahoma is one of a number of states that awards delegates to the top two finishers in each Congressional district.

It may be one reason why anti-Santorum ads are now running in Oklahoma, as the Romney team and his Super PAC try to knock down the former Pennsylvania Senator.

The optics of a Romney loss in Michigan could be brutal, especially with a number of states like Tennessee, Georgia, Oklahoma, North Dakota, Alabama, Mississippi and more that just don't trend towards him.

It is one reason you will see Romney in Michigan a lot over the next five days.