Former Massachusetts Gov. Mitt Romney and former Pennsylvania Sen. Rick Santorum are turning their attention to Michigan as they battle for the top spot in the race for the GOP presidential nomination.

Michigan's primary is February 28.

Romney has long been expected to win in the state of his birth, but recent polls show Santorum beginning to take a sizable lead in Michigan and nationwide.

The MRG Michigan poll shows Santorum with 43 percent of the vote and Romney trailing at 33 percent.

Now both candidates are taking to the Michigan airways, attacking each other to win over voters.

CBN News Senior Political Correspondent David Brody said Romney is determined to win the state where his father served as governor, and he's willing to spend big money to do it.

"Santorum has never gone up against the Romney machine one-on-one," Brody noted. "And that's exactly what's going to happen in Michigan. Romney's ready to drop $1.3 million in Michigan against Santorum.

But money spent on ads might not be enough.

Three years ago Romney opposed President Obama's plan to lend money to automotive giants General Motors and Chrysler.

The bailout saved thousands of blue collar jobs in Michigan. Those workers are now turning to Santorum.

"He is appealing to blue collar Republicans," Brody said. "He is basically a heartland type of guy."

Losing Michigan would be devastating to the Romney campaign since momentum from the state's primary will carry the candidates into Super Tuesday.

Meanwhile, President Obama is on the West Coast raising money. The president's fundraisers there are expected to raise more than $8 million for his campaign.