Will Michigan primary reconfigure the race?

>>> now to the other major story we're following tonight. republican primaries in arizona and michigan . that's tonight's big race because it's romney 's home state. a loss for him would be huge huge. peter alexander is on the trail for us tonight in michigan . good evening.

>> brian, good evening. at one time or another there have been seven different republican front -runners and mitt romney has had the most substantial organization and the most money but he's been unable to unite the party wind him. once all the votes are counted it could recon figure the entire race. even as michigan voters were casting their ballots today, mitt romney and rick santorum continued continued to exchange barbs.

>> he's an economic lightweight. he doesn't understand how the economy works.

>> he's a lightweight on conservative accomplishments.

>> reporter: facing questions about his difficulties motivating conservative voters, even in the state where he grew up, romney today pushed back.

>> you know, it's very easy to incite the base with incendiary comments. i'm not willing to light any hair on fire to get support. i am who i am.

>> reporter: seeking to upend romney for the nomination is woo key party activists, social conservatives and democrats, like small business owner herbert howell.

>> why did you vote for rick van santorum?

>> i feel like he's running on moral issues and i feel the country is getting away with that.

>> reporter: santorum's campaign targeted romney 's opposition to the bailout. romney 's troubles here, analysts say, are partly due to the state's anti-establishment political tradition.

>> it's in the republican dna here to be a little contrarian, independent, to buck the system.

>> reporter: this year, michigan 's primary is about muts more than michigan , a rust belt state in the heart of the economic troubles. a romney loss here could vote the race into disarray. speaking to union workers in washington, president obama focused on michigan , too.

>> ho's it going uaw!

>> reporter: trumpeting his position to bail out the auto industry .

>> some said we should let detroit go bankrupt. you remember that.

>> reporter: and not together forgotten, ron paul and newt gingrich . while he's not competing in today's primaries, gingrich's whose super pac received $7 million more from its top donor, he's focussing on super tuesday, including gingrich's home state of georgia where there are both delegates than both arizona and michigan combined.

>> peter alexander in michigan . thanks.