Voters head to the polls Tuesday in U.S. Republican presidential hopeful Mitt Romney's native Michigan in a key primary that once again may reset the course of a unpredictable Republican presidential race.
Republican Candidates Campaign ahead of Michigan and Arizon Primaries
Republican presidential candidate Mitt Romney leaves the stage to greet supporters at a campaign rally at the Royal Oak Theater in Royal Oak, Michigan on February 27, 2012. (AP)
Republican presidential candidate Mitt Romney shakes hands with musician Kid Rock after he performed a song at a campaign rally in Royal Oak, Michigan on February 27, 2012. (AP)
Republican presidential candidate Rick Santorum speaks during a campaign rally in Kalamazoo, Michigan on February 27, 2012. (AP)
Brothers, from left, Laine, Logan and Luke Hicks, recite the Pledge of Allegiance before Republican presidential candidate Rick Santorum speaks at a Kalamazoo, Michigan rally on February 27, 2012. (AP)
Republican presidential candidate Ron Paul waves after speaking at Michigan State University during a rally in East Lansing on February 27, 2012. (AP)
Supporters cheer for Republican presidential candidate Ron Paul during a rally at Michigan State on February 27, 2012. (AP)
Republican presidential candidate Newt Gingrich focused on Super Tuesday states, and spoke during a campaign rally in Nashville, Tennessee on February 27, 2012. (AP)
Supporters of Republican presidential candidate Newt Gingrich listen to him speak during a campaign rally in Nashville, Tennessee. (AP)