Florida Senator Marco Rubio’s third-place finish in the Iowa caucuses positions him as the mainstream Republican with the best chance of blunting the outsider campaigns of the candidates who finished ahead of him: Ted Cruz and Donald Trump.

Rubio, the 44-year-old son of Cuban immigrants, could peel away supporters of Jeb Bush, Chris Christie and John Kasich, the three other Republicans whose backing from newspapers, elected officials and financial firms gave them the imprimatur of the establishment.

Well before Cruz won the caucus on Monday, leaving Trump in second place with 24 percent of the vote, and Rubio with 23 percent, the Florida senator’s aides were downplaying expectations. Rubio strategist Todd Harris said the campaign would be satisfied with a third-place finish, which Harris said would strengthen Rubio’s standing in what may be a drawn-out nomination battle against Trump and Cruz.

“This is the moment they said would never happen,” Rubio told his supporters gathered for a caucus-night party in Des Moines. “For months, they told us we had no chance. For months they told us because we offered too much optimism at a time of anger, we had no chance. ”

With New Hampshire’s record of backing moderate, business-oriented Republicans, Kasich, Bush and Christie are likely to remain in the race at least until after its Feb. 9 primary, said Cary Covington, who teaches political science at the University of Iowa. Bush is likely to hang on longer, Covington said before Iowa’s results were reported.

Growing Momentum

After the Iowa result, U.K. betting company Ladbrokes Plc installed Rubio as the new favorite to win the Republican nomination, leapfrogging previous front-runner Donald Trump. Rubio was given odds of 4/5 to get the nod, equivalent to a 56 percent chance.

Rubio’s campaign spoke of growing momentum in the final week before the caucus, noting larger crowds at events and strong poll numbers. The campaign adopted the Twitter hashtag #marcomentum.

Rubio maintained in the week before the caucus that Cruz was the frontrunner. Rubio’s stump speech included criticisms of President Barack Obama, and the leading Democratic candidates, Hillary Clinton and Bernie Sanders. Rubio rarely mentioned his Republican opponents, unless asked.

Rubio has knocked Cruz for voting for a federal budget that included military spending cuts, and called Cruz nervous and defensive in the face of Trump’s leads in polls. Rubio has had little to say about Trump himself, though when the billionaire boycotted the Jan. 28 debate in Des Moines, Rubio likened the campaign to a circus. Rubio cast himself as a serious leader seeking a serious job.

Rubio’s campaign, built around the theme of "A New American Century," last year stressed optimistic themes but took on a darker streak as Trump and Cruz’s messages of a country in decline resonated with voters.

Uniting Republicans

Speaking to a caucus meeting in the Des Moines suburb of Urbandale, Rubio said he was the best candidate to not only unite social and economic conservatives in his own party but reach independent voters with a message of upward mobility for working- and middle-class Americans.

"If you caucus for me and I win, we will unite this party and grow this movement by taking our message to people who haven’t heard it before," Rubio told about 300 Republicans caucusing in a community center.

Terri Steinke, 57, who voted for Rubio, said she seriously considered Cruz but concluded that Rubio would fare better in a general election. She said she was swayed partly by Trump’s assertions that Cruz’s birth in Canada may make him ineligible for the White House.

"He’s young and he’s charismatic and he’s got a lot of energy," Steinke said of Rubio. "He comes across as sincere, honest. I’m sure he can reach across the aisle."

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