Earlier this month, I defended Mitt Romney when his rivals led by Newt Gingrich attacked his wealth and successful career at Bain Capital using left-wing tactics and rhetoric. I further puzzled at why Gingrich, heading into South Carolina, wouldn't just go after Romney from the right, given his record in Massachusetts on health care, guns, abortion and a host of other issues. In all of my anger at Gingrich for resorting to Michael Moore-style tactics, the most obvious explanation for Gingrich's behavior escaped me. But when Gingrich decided he'd release his tax returns, and turn the focus to Romney's refusal to release his at this time, the strategy became much clearer.

Nobody is South Carolina is ever going to mistake Mitt Romney for Sen. Jim DeMint. They already know that he's an imperfect conservative, to put it charitably. But Romney hasn't become the Republican front-runner because Republicans view him as the most consistent conservative, but as a result of the perception that he's the candidate with the best chance of beating President Obama.There may be limited additional benefit for Gingrich in attacking Romney's conservative credentials, but if he can undermine, at least to some degree, the electability argument, he has a chance of disrupting Romney's waltz to the nomination. So that's why he's essentially throwing everything at Romney that Obama is going to during the general election -- from his career at Bain to Romney's decision to take a long road trip with a dog on the roof.

Iowa entrance polls found that one out of four voters viewed being a "pure conservative" as the most important candidate quality, and only one percent of them went with Romney. But among the 31 percent who named the ability to beat Obama as their most important quality, 48 percent chose Romney -- the next closest being Gingrich at 20 percent. If Gingrich pulls off a come from behind victory on Saturday despite the conservative backlash against his left-wing tactics, my guess is that muddying the waters on electability will be a key reason.

Launching an attack on Bain, thus, wasn't a pure Kamikaze mission as some, including those in the Romney campaign, have described it. It was the only rational strategy for him to extend the race. This doesn't mean I agree with it now anymore than I did a week ago, but now it makes sense to me.