"We see a conservative, grass-roots Republican constituency that is cycling among candidates, and now that cycle is shifting to Rick Santorum," he said. "Republican primary voters are looking for two things: a true conservative and someone who can beat President Obama. Romney has always done well on the can-he-beat-Obama side of things. He is not now doing so well on the conservative side. What's happened with Santorum, he's seen as the true conservative, but it's not clear that he can beat Obama."
"Obviously, it would be a huge symbolic loss if he can't win his home state," said University of Michigan political scientist Michael Heaney. "If Romney loses in Michigan, the media will say his campaign is down, he's lost momentum and he's washed up now."