STEVE INSKEEP, HOST:
Four years ago, the Iowa caucuses were very, very good to former Pennsylvania Senator Rick Santorum.
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RICK SANTORUM: Game on.
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INSKEEP: Things are very different this time for the 2012 caucus victor. He is struggling for attention in a crowded field - struggling but not ready to quit. NPR's Scott Detrow reports.
SCOTT DETROW, BYLINE: With poll numbers low and consistent relegation to undercard debates, the 2012 Republican runner-up often finds himself justifying his campaign's continued existence.
SANTORUM: People say, why are you still doing this? And I remind people I was in the low single digits, you know, four years ago at this time three weeks out.
DETROW: And Santorum has to be thinking that he has a lot of the qualities Republicans are looking for this year. They're angry, and often so is he, even when he's talking to a small town hall of a couple dozen people in Des Moines.
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SANTORUM: You know why Donald Trump is connecting? Because people are sick and tired of being lied to. They're sick and tired of political correctness.
DETROW: In fact, when he talks about the Middle East, it's not an exaggeration to call Santorum's talk apocalyptic.
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SANTORUM: Both ISIS and Iran are fundamentalist Muslims who believe that soon, the Mahdi, their savior, is coming back at the end of times for the purpose of leading the final conquest of the West.
DETROW: Santorum has been focused on terrorism and Iran policy for decades. And that's what the race is all about right now. But so far, that 2012 success hasn't translated to this race. But he's right. He didn't really gain momentum last time until the final days.
ANNE SELZER: I remember kind of stopping dead in my tracks going, oh, Rick Santorum is in double digits.
DETROW: Ann Selzer conducts the Iowa poll for The Des Moines Register. She says last-minute surges or collapses aren't uncommon in Iowa. But Santorum's 2012 rise still took everyone by surprise. The paper had already mocked up its headline when she brought the final poll numbers in a couple days before the caucuses.
SELZER: And when we came in and said, you need to add Santorum to the picture, their jaws just dropped open.
DETROW: Santorum prevailed by earning support from evangelical voters, a powerful block in the caucuses. But this time around, those people appear to be looking elsewhere. Among people who caucused for Santorum in 2012, Selzer says...
SELZER: They are more likely to say that they are supporting Ted Cruz than any other candidate by 4 to 1.
DETROW: Cruz has many of the same characteristics as Santorum. He's a hawkish sometimes-bomb-thrower who plays well with evangelicals.
SANTORUM: Look, I understand this is a very, very, very, very, very different environment than four years ago. And people say, well, that's not going to work this time. Well, we'll wait and see.
DETROW: The former senator still has his backers. Des Moines lawyer Bill Brown says he's wary of the relative inexperience of the candidates on top of the Iowa polls.
BILL BROWN: We need somebody that really can deal with what they're dealt with in the Congress and work their way through it.
DETROW: Buoyed by people like Brown, Santorum is determined to keep plugging in Iowa, doing town hall after town hall, even if only a handful of voters show up.
SANTORUM: And hopefully, you know, impressing people enough so they'll go out and say, hey, you know, now I know why I voted for that guy last time around.
DETROW: He's got two weeks to make that case. But Santorum knows from experience that can be enough time to turn things around. Scott Detrow, NPR News, Des Moines, Iowa.