LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Mike Huckabee listens to Rick Santorum speak during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)

IOWA FALLS, Iowa – Rick Santorum was right on schedule, strolling into the Coffee Attic at 4 p.m. for his fifth event of the day. He shook hands, posed for pictures in his iconic grey sweater vest, and peered into the room where just a dozen potential voters were waiting to meet him.

“It’s not as many as we’d like,” admitted Andy Cable, a local Republican Party committeeman.

“We’ll take what we have, and convert ‘em into activists,” Santorum said.

It took Santorum just 67 seconds to take a whack at Sen. Ted Cruz (R-Tex.), warning his audience that an anti-ethanol candidate was “in serious contention of winning the state of Iowa, if you believe the polls – which I do not.” Without ever mentioning Cruz, Santorum went on to mock “tough guys” who “don’t win fights” and explain why “on-the-job training doesn’t work.”

For the first time in the short history of Iowa’s caucuses, two of its winners – 2012 victor Santorum, 2008 winner Mike Huckabee – were running against each other. Both men had seemingly been banished to irrelevance as a tireless and well-funded Cruz convinced scores of powerful social conservatives, everyone from James Dobson to Glenn Beck, that only he could win.

In the most recent Des Moines Register/Bloomberg Politics poll, the one that captured both men’s winning surges, Cruz stood at 25 percent, Huckabee at 3 percent, and Santorum dead last at 1 percent. But Cruz is struggling to put away Donald Trump, and the one-time winners couldn’t be happier about it.

“In 2012, 40 percent of people who voted for me decided in the last couple of days,” Santorum told an early morning crowd in Lake Mills, a small town near the Minnesota border. “Because of the food fight between the top two candidates, you’re going to have a ton of people showing up who are not decided.”

That’s exactly what Cruz and his allies are afraid of. In recent days, with increasing volume, they’ve been warning social conservatives that to abandon Cruz is to hand Iowa to Donald Trump. Only Cruz, they say, has the wherewithal to actually defeat the “establishment” and become the nominee. In a Monmouth University poll released on Wednesday, just 7 percent of Republican voters had been contacted by the Huckabee campaign. Just 5 percent had been contacted by Santorum’s campaign – one-fifth as many who had been contacted by Cruz.

“This is your opportunity to choose well,” Bob Vander Plaats, an influential Iowa evangelical leader who is supporting Cruz, told a crowd in Ottumwa on Tuesday.

“It’s not about voting against Governor Mike Huckabee, it’s not about voting against Senator Rick Santorum… the coach in me wants to look at you as though this is a locker room and say it’s down to two men. It’s between Donald Trump and Ted Cruz.”

Vander Plaats, who chaired Huckabee’s 2008 campaign here and who gave a crucial 2012 endorsement to Santorum, epitomized Cruz’s strategy. Throughout 2015, the Texan picked off key supporters and organizers, even poaching Huckabee spokeswoman Alice Stewart.

At a private meeting with pastors on Monday, Cruz didn’t mention the candidates by name, but told the group that he is the only social conservative who can blunt Trump’s national momentum.

“Let me talk for a moment if you happen to be thinking about another candidate beyond the two of us,” Cruz said. “There are a lot of good people in this race. A lot of people who I like, who I respect, who are friends of mine, who I’ve no intention of insulting.”

Cruz called the race a “dead heat,” and warned that if Trump wins Iowa he will be in the lead in New Hampshire and could be “unstoppable” if he wins there.

“So even if you’re thinking about another candidate, the simple reality is there is only one campaign that can beat Trump,” Cruz said.

Rep. Steve King (R-Iowa), who has been barnstorming the state for Cruz, said there isn’t any other choice for Republicans aside from Cruz or Trump.

“This is a binary decision now in Iowa. Caucus goers are going to know this. You vote for Cruz or you vote for Trump,” King said.

That scenario did not particularly bother Huckabee or Santorum. Where Cruz sees a potential Trump victory here as the start of a landslide, other campaigns see it as the beginning of the end for the candidate they consider a slippery opportunist. Perhaps Cruz peaked too early. Perhaps, like Howard Dean in 2004, he would be sullied in a fight with another front-runner, allowing Santorum or Huckabee to rise and notch another miracle.

“I got a call from somebody last night, saying they were going to endorse Cruz,” Santorum said in an interview after his morning event. “I said, ‘I think that’s a mistake. He’s not catching on. He’s got a lot of issues even social conservatives are worried about, like his stance on marriage, and you’re giving him a pass.’ Fine, go ahead, make him the standard-bearer, but what you’ve done is make it harder for me and Mike to break through.”

Huckabee was even bolder in his disdain for Cruz. Ever since the New York Times released a tape of Cruz telling a New York donor that banning gay marriage would not be a “top three priority” for his administration – Cruz said he would defend “the whole Constitution,” effectively leaving marriage to the states – Huckabee has insisted that the Texas says “one thing in Muscatine [Iowa] and another thing in Manhattan.” And a pro-Huckabee super PAC has put $1.1 million behind an ad campaign that casts Cruz as a “phony” Christian. In the radio and TV spots from Pursuing America’s Greatness, two women bemoan how Cruz “doesn’t tithe” and his wife Heidi worked at Goldman Sachs before the candidate secured a crucial loan guarantee for his 2012 Senate bid.

On Wednesday, speaking to around 50 voters at a pizza restaurant in Ames, Huckabee repeatedly leaned into those attacks, warning of candidates backed by “Citigroup and Goldman Sachs,” and asking how much better the country might be if Christians tithed 10 percent of their earnings.

“I don't want to comment on what he gives or doesn't,” said Huckabee in an interview after the speech. “My view is this: On a spiritual level, it’s really hard to say that God is first in my life if he’s last in my budget.”

The former Arkansas governor was even more comfortable chastising Ted and Heidi Cruz for the 2012 loans. “How many people out here could do that?” said Huckabee, pointing to the people who had come to see him. “Could you do that? I couldn’t, either. If you’re going to say ‘I’m not one of those insiders in the cartel,’ but you get the money only the cartel gets, and your background is that you worked for the cartel, and that was the launch of your [political] career, how do you say: Oh, that’s not me?”

Santorum’s approach to the Cruz problem was dogged, but less personal. “I’m not going to attack Ted Cruz for not being a tither,” he said. “Let’s talk about issues.”

But like Huckabee, he was warning as many voters as he could that a Cruz victory would squander Iowa’s power – and the power of social conservatives – on a candidate who did not deserve it. And both men, despite the polls, retained plenty of credibility with voters. Penelope Miller, a likely caucus-goer who saw Huckabee in Ames, said that the Pursuing America’s Greatness ad had helped lock in her vote. But she assumed that the ad had come from Trump.

At this week’s campaign events, Cruz’s supporters were acutely aware that the conservative vote might end up splitting against them. They were equally aware of the problems: Rick Santorum and Mike Huckabee.

“If they don’t have any real backing they need to step aside,” said Carl Bockenstedt, a Cruz supporter from Dyersville, Iowa. “Senator Cruz can get those votes.”

Neither man was going to go along with that. In Iowa Falls, after Santorum finished speaking, a 2012 supporter named Dave Sweeney agreed to serve as a caucus captain this time.

“My speech is going to be: Don’t think you have to vote for a front-runner,” Sweeney explained. “It’s who comes in third, fourth, fifth that matters. We can accomplish more that way.”