The out-of-context quote most commentators have fairly dimissed aren't going away. And even liberal bloggers are being more charitable than Romney's Republican opponents:
John Weaver, who is Mr. Huntsman’s top adviser, said Monday that Mr. Romney “will rue the day he said that.” A “super PAC” backing Mr. Gingrich revealed Monday that it plans to significantly amplify that attack on Mr. Romney in South Carolina, where it plans to spend $3.4 million to blanket the television airwaves with television ads.
I think Romney has had a bad few days. We'll see if it has damaged him tomorrow night.
Update: Taegan thinks it's a dangerous gaffe:
Romney's comment is actually quite similar to John Kerry's, "I voted for it before I voted against it." The context didn't matter and the damage was done.
Matt Bai agrees – because the gaffe reinforces a key, existing worry about the candidate, and could define him in ways that the general election would punish. Hence the danger that his "electability" card could fray. He'll need all that Bain SuperPac money in South Carolina, won't he?