Tuesday could be a nail-biter of a day and night for Republican presidential frontrunners Mitt Romney and Rick Santorum as they await the results of two key primaries. Thanks to early voting, Romney has a sizeable edge in Arizona, leading Santorum by an average 41.4 percent to 28.2 percent, but will voters in his native state of Michigan give him the nod?

According to recent polls, it’s too close to call due in large part to two weeks of million-dollar mud-slinging. In a Mitchell Research poll conducted for Michigan Information & Research Service, Santorum leads Romney by 34 percent to 25 percent, while a Public Policy Polling survey has Romney on top at 39 percent to Santorum’s 37 percent. And because Michigan has an open primary process, mischievous Democrats could try to influence the contest by casting ballots for Santorum.

But, no matter the outcome, the former Massachusetts governor has got the most at stake, says David Bositis, senior political analyst at the Joint Center for Political and Economic Studies.

“It would be a really bad sign and a reflection of the fact that the Republican Party is really split and a lot of people just don’t like him,” Bositis said. “Part of that’s because they don’t trust him and they don’t think he’s a real conservative.”

There’s also Romney’s politically tone deaf way of highlighting his fabulous wealth by saying things that frankly seem crazy, Bositis adds, particularly at a time when voters very much want candidates who can at least empathize with the struggles of ordinary Americans. Santorum, meanwhile, is putting his working-class roots and conservative bona fides to good use.

A Romney loss in Michigan would be a boost for the former Pennsylvania senator and ultimately President Obama, who is already benefitting from the costly and prolonged Republican slugfest. In a new Politico/George Washington University poll, Obama is leading the two frontrunners by more than 50 percent in most matchups.

Nor would a win mean it’s over, with Super Tuesday looming, when several states hold their primaries next week. According to Bositis, Romney is running third in some states, including Oklahoma and Georgia.

Newt Gingrich and Texas Rep. Ron Paul, meanwhile, trail Santorum and Romney by several points in most polls except Georgia, where the former House speaker is ahead. The two will likely stay in for as long as it’s still fun and they have money to run.

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