Former Massachusetts Gov. Mitt Romney gestures while delivering remarks at the Heritage Foundation in Washington, Monday, June 1, 2009. (AP Photo/Manuel Balce Ceneta)
MICHIGAN, ARIZONA (CBS NEWS) -- After all the votes are counted, Mitt Romney will have won the Arizona Republican primary, CBS News projects. Based on exit polling estimates, Romney has a slight edge over rival Rick Santorum in a hard-fought race in Michigan. Votes are still being counted in both states, and CBS News has projected the former Massachusetts governor the winner in both contests.
While Romney has long held the lead in Arizona, the race in Michigan has been unexpectedly competitive and one of the closest of the GOP campaign so far. Though Romney was born in Michigan and his father was a governor and top auto executive there, Santorum surged ahead of his rival in early February as voters connected to the social conservative. Romney regained his footing in recent days and polls showed the two candidates in a statistical dead heat going into Tuesday's contest.
With 1,625 of 5,233 precincts reporting in Michigan, Romney has 41 percent of the vote. Santorum has 38 percent while Ron Paul has 12 percent and Newt Gingrich has 6 percent.
While the number of delegates at stake are roughly the same for both states, Michigan is more closely watched because the second place finisher will garner some of the delegates, and the results are also seen as a referendum on Romney's candidacy.
With former House Speaker Newt Gingrich essentially ceding the state and Rep. Ron Paul trailing in the polls, the Michigan primary could serve as a pivotal test as to whether Republican primary voters are more interested in a polished, diligent candidate like Romney or a passionate populist like Santorum.
CBS News early exit polling shows that Arizona and Michigan primary voters are primarily concerned with picking a candidate that can defeat President Obama. Among the issues they care about, voters said the economy is the most important.
When it comes to electability and handling the economy, early exit polling shows Michigan voters have the most faith in Romney. When asked which candidate has the best chance of defeating Mr. Obama in November, 52 percent of Michigan voters picked Romney. Another 26 percent said Santorum, while 8 percent said Gingrich and 7 percent said Paul.
Among Michigan voters who picked the economy as their top issue, 46 percent backed Romney, while 28 percent supported Santorum.
Among Arizona voters who picked the economy as their top issue, 47 percent backed Romney, early exit polling showed, while 30 percent backed Santorum. Romney is seen as most electable in Arizona.
If Romney can pull off a victory in Michigan, he'll dodge getting an embarrassing black eye on his home turf. A win would also give the former Massachusetts governor some crucial momentum ahead of Super Tuesday on March 6, when 10 states will weigh in and a whopping 437 delegates will be decided.
Yet even if Romney wins, the competitive race in Michigan already underscores the candidate's weaknesses. In spite of his well-organized campaign, Romney has been incapable so far of winning robust support from his own party.
If Santorum wins in Michigan, it will be an impressive victory, giving credence to the mix of economic populism and social values that he's delivered on the campaign trail. Santorum has tailored that message to appeal to a group once referred to as "Reagan Democrats" -- working class, social conservatives.
A victory for Santorum would leave him well poised for Super Tuesday, when three important Southern states will vote: Tennessee, Oklahoma and Newt Gingrich's home state of Georgia. Santorum could also do well in Ohio, a key swing state where polls show him currently leading. However, Santorum may still be hounded by questions of whether his campaign can appeal to more than just the conservative base.
CBS News early exit polling in Michigan showed that white working class voters -- the voting bloc Santorum has been chasing -- has split between the leading candidates. Thirty-eight percent of white voters without a college degree and earning less than $50,000 backed Santorum, while 37 percent backed Romney.
Regardless of the outcome in Michigan, the race could go on for a number of months. A candidate needs 1,144 delegates to secure the nomination; even after the Michigan and Arizona delegates are allocated, the candidates will still be far from what they need for victory.
Michigan's 30 delegates will be awarded proportionally, which benefits Ron Paul, who has focused on accumulating delegates if not winning states outright.
Going into Tuesday, Romney lead in CBS News' Delegates to Date Estimate, with 115 delegates. Santorum had 47, while Gingrich had 30 and Paul had 15.