I think the Associated Press has it right with this headline:Santorum’s early success pushed GOP to the right

From this Democrat’s point of view, he lifted up the rock which had hidden all the GOP nastiness Romney didn’t want to get near and forced Romney to take social positions he’d have presumably preferred not to take. I’m pretty sure Romney would much prefer to fight Obama on domestic economic policy, but he’s left himself wide open to charges that he’s anti-woman by his support of the Blunt Amendment, which would allow employers to take “conscience exemptions” from health insurance which could deny their employees birth control or any other health coverage the employer felt was “morally objectionable.” He’s also had to flip-flop on many of his previously-held views just to survive the GOP primaries (Romneycare, Roe v. Wade, the Bush-Obama stimulus). The one thing he’s been steadfast on is just as dumb: he’s continued to say he was against the auto companies bailout despite much evidence that it’s succeeded far beyond most hopes.

It’s down to Romney and two remaining members of the clown car (Gingrich, Paul) before the real game begins.