Rick Santorum has been a cosmically unlucky presidential candidate. The Google-challenged former U.S. senator staged a last-minute rally in Iowa to essentially tie Mitt Romney for first. Yet an initial, eight-vote shortfall was enough for Romney to score the Hawkeye State a win and use it as a launching pad for an easy victory in New Hampshire. Robbed of any real momentum from Iowa, Santorum finished a distant fifth there.

Santorum, of course, got a smidgen of redemption yesterday morning when Iowa Republican officials said the final tally gave him a 34-vote lead over Romney. But who cares about stale caucus results? Hardly anyone, it turns out, especially not when there’s plenty of fresh news such as Rick Perry turning into Texas toast and Newt Gingrich’s ex-wife Marianne claiming the former House speaker wanted an “open marriage” like some Hollywood libertine.

"Is a 'faith and family' campaign — and two flawed opponents — enough to get Santorum first over the finish line? Maybe, with a little luck." --James Pethokoukis

Yet Dame Fortune may yet give him a smooch. Santorum lost one of his main rivals for evangelical voters when Perry dropped out yesterday. And the revelations of Gingrich’s marital past could well destroy the former speaker’s chances with Christian conservatives.

So, although recent South Carolina primary polls have Santorum stuck in the low teens, he’s probably best positioned since Iowa caucus night. He’s in the final four, after all. And one member of the remaining quartet is Ron Paul, a niche candidate probably unacceptable to the vast majority of Republicans.

His other major obstacle to the GOP nomination is, of course, Mitt Romney. But the former Massachusetts governor is vulnerable to Santorum’s agenda, a mix of social conservatism and populist economics.

First, Santorum needs to become the Last Non-Romney Standing. That means knocking off Gingrich, whose support among evangelicals, as I mentioned, could soon plunge.

Then there’s front-runner Romney, who keeps reminding America’s cash-strapped voters that the rich really are different from you and me. They pay a lower tax rate. They have money in offshore accounts. They think making nearly $400,000 from giving speeches is “not very much money.” Santorum, by contrast, is the grandson of a coal miner, a biographical tidbit he never fails to mention on the stump. He also has an economic platform specifically geared toward middle-income families, such as expanding tax deductions and credits for children.

Is a “faith and family” campaign — and two flawed opponents — enough to get Santorum first over the finish line? Maybe, with a little luck.

James Pethokoukis is a columnist at AEI and a CNBC contributor