Santorum revels in sudden support — but how deep?

BOISE, Idaho. — The latest Republican to surge in polls, Rick Santorum is trying to turn his newfound strength into something lasting.

Curious Republicans now pack his rallies. Supporters have funneled nearly $4 million to his formerly empty campaign account over the past seven days. And his staff is plotting an aggressive strategy to challenge Mitt Romney in Romney's native Michigan and beyond.

But things don't look so strong just beneath the surface.

Santorum is underfunded and outmanned. He's still lacking in organization, a month and a half into the primary season. And, after he won three contests in a single day last week, his opponents — on the right and the left — have begun their own efforts to tear him down.

An upbeat Santorum faced more than 1,000 people in a Boise high school auditorium Tuesday night and said his ideas would carry him through.

He said he's someone "who can overcome the disadvantages of money and media attention and still be in a position to win. Ideas matter."

But his challenges were on display the day before in Tacoma, Wash., where hundreds of supporters waited on cold, wet cement stairs in the dark to see the Republican presidential candidate with whom they're barely familiar.

"I don't know a lot about him, except I know he's more conservative than some of the other candidates like Mitt Romney," said Tanya Franklin, a 54-year-old airline reservationist, who says she'll probably vote for Santorum in her state's March 3 caucuses.

The former Pennsylvania senator has surged to a virtual tie with Romney in nationwide polling following his surprising sweep in Colorado, Minnesota and Missouri last week. But, as Franklin suggests, his popularity may have less to do with who he is than who he isn't. Santorum is not Romney. And with Newt Gingrich's recent decline, that's enough for some conservatives — at least for now.

Santorum had 30 percent support to 28 percent for Romney in a national poll released this week by the Pew Research Center. But the same poll said 31 percent of all adults had never heard of or couldn't rate him. That's a significantly higher number than for Romney, Gingrich, or Ron Paul. Even among Republicans, one in five told Pew they didn't know enough about Santorum to rate him.

Romney and others are now working to make sure that changes.