"This year, we can have someone who has a proven, consistent conservative message," said Jack Whitver, an Iowa state senator and co-chairman of his Hawkeye State campaign.
"Consistent conservative" also happens to be one of the main themes of Ted Cruz's campaign.
As Rubio is quickly becoming the choice of Republican lawmakers on Capitol Hill, he also is methodically trying to position himself as an anti-establishment hero with deep social conservative values -- not unlike Cruz.
In his stump speech, the Florida senator says his campaign is a repudiation of a GOP establishment that told him to "wait in line" in 2016 -- just like in his 2010 Senate race when he took down the party leadership's favorite candidate, Charlie Crist. He leans heavily into his religious views and anti-abortion stances in TV ads, a direct pitch to the evangelical voters who dominate the caucuses here and are a source of support for Cruz.
And in a new interview with CNN, Rubio sided with Cruz in the 2013 battle over Obamacare that prompted a 16-day government shutdown, a fight that enraged the party establishment but made the Texas Republican a hero on the far right.
"It's never a mistake to fight against Obamacare," Rubio said when pressed if he still agreed with the Cruz shutdown tactic. "All of us were involved in the effort to stop Obamacare."
Despite being viewed widely in Washington as an "establishment" favorite, Rubio's comments are an indication that he views his own candidacy differently as he heads into the final two weeks of campaigning in Iowa.
Unlike other candidates who draw support from one wing of the party or another, Rubio is trying to present himself as the lone candidate who can draw support from the various elements of the Republican coalition. In one breath, he talks about the United States as a "great nation in decline," not unlike the apocalyptic tones that lace Cruz speeches, and in another, he offers a positive forecast for a country he calls the greatest nation in the "history" of mankind.
That strategy presents its own pitfalls, particularly if no one group ends up particularly enamored with him. And trying to appeal to both the party establishment and the conservative base makes him a bigger target for his rivals, taking fire from the likes of Jeb Bush, Chris Christie and Cruz, all of whom characterize Rubio as a smooth-talking senator of little substance. After hearing Rubio's pitch last week, many voters were still keeping their options open.
Rubio brushed back suggestions this week when asked if he was trying to placate too many elements of the party all at once.
"These are the issues this campaign is about, so that's why I'm talking about them," he said.
But it also gives Rubio a chance to compete beyond Iowa and New Hampshire, even if he doesn't end up the winner in either of those first two contests. By stressing social issues, Rubio can win the social conservatives important in Iowa; military-minded voters in New Hampshire and South Carolina could be attracted to his hawkish foreign policy views.
And Rubio and his team believe if he ends up as the clear alternative to either Cruz or Donald Trump, much of the party could unite behind his candidacy, squeezing out the other establishment-backed candidates in the race. To win, however, Rubio believes he has to win enough support from movement conservatives in order to move beyond his consistent third-place standing in many polls.
And that means lashing Cruz -- and courting voters leaning in the Texas conservative's direction.
Rubio's attacks have been escalating against the Texas Republican since November -- on everything from immigration, national security, intelligence gathering and taxes. And in an attempt to cut at Cruz's own conservative credibility, Rubio has been slashing the Texas freshman for political pandering to the right wing of his party.
Echoing Rubio's comments on the trail, his super PAC, Conservative Solutions PAC, unveiled two slashing attacks against Cruz as part of a multi-million dollar ad buy in early primary states.
"What's changed for Ted?" the narrator asks in the ad. "He wants your vote. Ted Cruz, consistently calculated."
Cruz campaign spokesmen did not respond to requests for comment.
Choice of Capitol Hill
A growing number of lawmakers, including party leaders, now view Rubio as perhaps their best candidate to give the GOP the White House and keep control of Congress. Over the weekend, South Dakota Rep. Kristi Noem and Colorado Sen. Cory Gardner, two younger Republicans, stumped on behalf of Rubio, trying to underscore his message that the party needs a fresher face and a new generation of leaders.
But complicating that message are the many senior Republicans who are ready to jump behind him too, as the veteran Oklahoma Sen. Jim Inhofe did earlier this month. The other problem: The more lawmaker endorsements come Rubio's way, the more it cuts against his effort to showcase himself as an outsider who can shake up a stodgy institution.
"I think he's had some success in getting people on his team, and I think he's done a really good job out there," South Dakota Sen. John Thune, the No. 3 Senate Republican, said of Rubio. "Although I always tell people I'm not sure you want people of Congress endorsing you."
Rubio's campaign pitch to conservatives
On the air, Rubio's message is directly largely at movement conservatives. He talks about his devout Roman Catholic faith, saying in one ad that "the purpose of our life is to cooperate with God's plan." He says he'd limit abortions as president, calling it a "human rights issue." And on immigration, he declares there would be "no amnesty" if he became president, taking a hard line on an issue that suggests he's not too far away from Trump on the issue, despite having a more moderate record.
But while he doesn't advertise it, Rubio's record on immigration is more in line with the party establishment. After co-authoring the Gang of Eight immigration bill in 2013, Rubio later backed away from it -- but still supports individual pieces of it, including eventually offering the 11 million people here illegally the opportunity to obtain green cards and apply for citizenship.
In the interview with CNN, Rubio tried to insist that backing a pathway to citizenship is hardly tantamount to amnesty. He said that those who came into the country would have to suffer consequences, even though many would be allowed to stay in the United States and eventually become citizens.
"Amnesty is the forgiveness of wrongdoing without consequences," Rubio said. "There will be consequences for violating the law."
By playing in both the establishment and tea party lanes, Rubio backers hope he's the one person who can bridge a party divided by a bitter primary season.
"We can have someone that is the most articulate messenger of the conservative movement today in Marco Rubio," Whitver said.