And in Michigan, there's a fight going on over one delegate to the Republican National Convention. Rick Santorum's campaign team says its candidate is a victim of, quote, thuggery. They accuse Michigan Republican leaders of engineering an after-the-fact rules change to give Mitt Romney a slim lead in delegates from last Tuesday's state primary.
We have more from Michigan Public Radio's Rick Pluta.
GOP presidential candidate Mitt Romney plays up his Michigan roots when he talks to voters in the state where he grew up.
In 2008, Romney won the Republican presidential primary in Michigan. On the campaign trail, he likes to tell stories about his father, George, who was an iconic governor of Michigan in the 1960s:
"He said, 'It sure is great to be in Mount Clemens today,' even though he was in Mount Pleasant. My mother was sitting behind and said, 'George, it's "Pleasant." ' He said, 'Yes, it's pleasant in Mount Clemens.' "
GOP presidential candidate Fred Karger hopes Michigan's primary rules will allow him to pick up a few delegates to the national convention. He's focusing on just one congressional district in the center of the state.
Credit Rick Pluta for NPR
Karger has spent a lot of time at Michigan State University, where he's trying to appeal to supporters of President Obama. Any registered voter can cast a ballot in Michigan's GOP primary.