McClatchy writers ask the question:

Santorum is peaking in Iowa, but then what? By WILLIAM DOUGLAS AND DAVID LIGHTMAN

Former Pennsylvania Sen. Rick Santorum has gone from afterthought to X Factor in the Republican presidential field during the closing days before Tuesday’s Iowa caucuses.

Through a combination of relentless campaigning, misfortune falling upon some of his GOP rivals, and a still-unsettled electorate, Santorum has risen from being a single-digit bottom-dweller to a third-place contender with aspirations of surprising front-runners Texas Rep. Ron Paul and former Massachusetts Gov. Mitt Romney on caucus night.

A new Des Moines Register Iowa poll dramatically illustrated Santorum’s potential. Romney led the survey, taken Tuesday through Friday, with 24 percent of likely caucus-goers. Paul was second at 22 percent, followed by Santorum at 15.

But results from Thursday and Friday showed a Santorum surge. Romney still led with 24 percent, but Santorum had vaulted into second at 21 percent, followed by Paul at 18. But can the Santorum surge last?

In this topsy-turvy campaign in which six candidates have taken turns at the top, nobody knows for sure. But the conservative ex-senator is clearly enjoying the new attention after spending most of the year stumping through the Hawkeye State in near obscurity. “If we do well here we get on the national stage,” Santorum told McClatchy Newspapers as he hosted an Iowa State-Rutgers University football game viewing party Friday at a restaurant in Ames, Iowa.

What a difference a bump in the polls makes. An NBC News/Marist College poll released Friday showed Santorum in third place at 15 percent among likely Republican caucus-goers, placing him behind Romney at 23 percent and Paul at 21 percent. Fifteen percent might not seem like a big number, but it’s a long way up from the 6 percent Santorum registered in a similar Marist survey in early December. More importantly, Santorum has clawed his way past former House Speaker Newt Gingrich, who represented Georgia and whose numbers are fading under a barrage of negative attack ads, and Texas Gov. Rick Perry, who’s struggling to regain the confidence of caucus goers after his poor performances in televised debates. “He’s been slowly building a grassroots following,” said Craig Robinson, editor of the Iowa Republican, a GOP newsletter. “He has the ability to challenge Ron Paul and Mitt Romney on caucus night. He’s had quite a week.

He’s won the battle of the news cycle every night.” Robinson said Santorum’s new status is a testament to his old-school campaign doggedness - he’s held over 350 town hall meetings and visited all of Iowa’s 99 counties at least once - and his appeal to Iowa’s evangelical and Christian conservative Republicans, who’ve been shopping for a candidate to rally around. Gingrich’s drop has also prompted some Iowans to give Santorum a second look. “He getting that second wave, the splash created by the Gingrich collapse in the never-ending search by Republican conservatives for who’s an acceptable conservative,” said Lee Miringoff, director of the Marist College Institute for Public Opinion.

There are no questions about Santorum’s conservative credentials.

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Santorum is the Religious Right’s last hope. I can easily see them rallying around him for the rest of the campaign season.