A large majority of commenters are arguing that Rick Santorum can win the nomination. Zoltan Newberry writes: “Santorum is authentic. He is relaxing and becoming more personable and attractive. Yes, he can win.” Newshound11 makes this case:

Of course Santorum has a chance — a realistic chance — to beat not only Romney for the nomination but also Obama for the presidency. Just consider the “but” constituencies now in play.

* With the GOP, the “anybody but Romney” segment is very large, highly energized, and earnestly looking for an alternative. If Santorum can get on message with the economy and resisting being led up social side streets, he could capture that segment and win the nomination.

* With a huge and growing mix of Americans saying “anybody but Obama” in 2012, whoever wins the GOP nomination will have a fair shot at winning the votes of that “but” segment and carrying the election.

It’s a long way to November, and Romney is a very long way from having it all sewn up.

But there was a strong and forceful contingent on the other side, arguing that a Santorum win is implausible. Larry 3435 writes: “Santorum’s turn at being not-Mitt will flame out even faster than Gingrich’s. We are really scraping the bottom of the not-Mitt barrel now. The interesting question is whether the only remaining potential not-Mitt, Huntsman, will get his turn. That would be funny, since Huntsman IS Mitt, only more so. “

Rodomontade reasons:

It’s harsh to call Senator Santorum a “one-hit wonder,” but I doubt he threatens Governor Romney any more than Huckabee threatened McCain. If there prove to be effective lines of attack on the Senator, he could easily be less threatening.

Participating in the Iowa caucus, because it requires voting and attendance at certain times and places, is more burdensome than voting in a primary. This favors candidates with zealous constituencies like Senator Santorum’s (and Representative Paul’s), and disfavors other candidates. He will find it harder to replicate his success in Iowa elsewhere — though he will certainly experience a bounce in support.

The media, undoubtedly goosed along by the President’s minions, has made too much of Republican reluctance to support Governor Romney. Whatever reluctance supporters of rival candidates may feel now in the heat of battle to support any potential nominee will fade when the alternative is re-electing the President. I don’t think the divisions in 2012 will be any more crippling than the divisions that the Democrats experienced in 2008.

My own take is that Santorum is the smartest, most credible of the not-Romney contenders. He faces an uphill battle, made more difficult by New Gingrich’s insistence on staying in the race. But in many ways South Carolina is tailor-made for him, both because of his strong stance on national security (which can attract votes from the large military and veteran electorate) and his social conservatism. He’s the underdog, but it would be a mistake to write him off.