Republican presidential candidate Marco Rubio aimed to outpoll rival Ted Cruz in Nevada’s caucus on Tuesday to bolster his position as the establishment favorite for his party’s nomination for the Nov. 8 election.

Looming over the tight race between the two first-term Cuban-American U.S. senators is Republican front-runner Donald Trump, the billionaire businessman who has won two of the first three state nominating contests and was expected to dominate the field in Nevada.

With Trump, a blunt-spoken political outsider, commanding a double-digit lead in a handful of Nevada opinion polls, political strategists in the state said Rubio and Cruz had a more modest goal: a clear win over the other, which could propel them through the busy voting month of March.

“They’re playing for second,” said Nevada political analyst Jon Ralston.

A recent CNN/ORC poll put Trump ahead by 26 percentage points in Nevada, at 45 percent, followed by Rubio, from Florida, at 19 percent, and Cruz, from Texas, at 17 percent.

Lagging behind were retired neurosurgeon Ben Carson — who on Tuesday stoked controversy by suggesting that President Barack Obama, the first African-American president, was “raised white” — and Ohio Gov. John Kasich. Carson was at 7 percent and Kasich was at 5 percent.

Kasich, who finished second to Trump in the Feb. 9 New Hampshire primary, kept his focus on bigger states, including Michigan and Virginia.

The rivalry between Rubio and Cruz, who won the first-in-the-nation Iowa caucuses on Feb. 1, has intensified as both seek a boost going into the nominating contests in a dozen states on March 1, known as Super Tuesday.

On Saturday, Rubio beat Cruz by fewer than 1,000 votes for second place in South Carolina’s Republican primary.

Strategists said Rubio is benefiting from the withdrawal from the race of one-time establishment favorite Jeb Bush, some of whose donors were preparing to shift to Rubio immediately after Bush dropped out on Saturday night.

Rubio has picked up endorsements from several Nevada party leaders, including U.S. Sen. Dean Heller and Nevada Lt. Gov. Mark Hutchison.

His campaign staff was due to be joined by Marc Short, a senior political adviser to the billionaire industrialist brothers Charles and David Koch, Politico reported on Tuesday. The influential brothers, who have not endorsed any candidates, spend tens of millions to advance their libertarian brand of politics, which would sharply limit the role of government.

The Cruz campaign, meanwhile, lost a key staffer on Monday when the candidate fired his main spokesman, Rick Tyler, for posting a video that falsely showed Rubio dismissing the Bible.

Complicating the already bumpy path to victory for Cruz, lingering questions over the Texan’s birthplace continue to dog his campaign. He was born in Canada, in the western city of Calgary, to a Cuban father and U.S. citizen mother.

Cruz on Tuesday asked a federal court in Houston to throw out a class-action lawsuit questioning his eligibility to be president.

Trump, known to verbally savage rivals, including fueling questions over Cruz’s birthplace eligibility, appeared to continue to focus his venom on Cruz.

Cruz “lies like a dog,” Trump wrote on his Twitter account, saying in a separate message that Cruz fired his spokesman “like a dog.”

“Ted panicked,” Trump wrote.

Rubio, the son of former casino workers who spent six years in Nevada as an adolescent, is playing up his ties to the region.

“He’s not pushing it hard, like, ‘I’m really a Nevadan,’” said Eric Herzik, a political science professor at the University of Nevada-Reno. “But both he and his surrogates have highlighted he has the best understanding of Nevada because he actually lived here.”

Ralston estimated only 8 percent to 10 percent of eligible voters may turn up to caucus on Tuesday — or somewhere between 33,000 and 42,000 people, according to data from the Nevada secretary of state on registered Republican voters.