(Reuters) - Republican presidential candidate Marco Rubio aimed to capitalize on rival Ted Cruz’s recent missteps leading up to Tuesday’s Nevada caucus, where a strong finish could bolster his position as the establishment favorite for his party’s nomination.

Republican U.S. presidential candidate Donald Trump flexes his muscles as he talks with caucus participants while visiting a Nevada Republican caucus site at Palo Verde High School in Las Vegas, Nevada February 23, 2016. REUTERS/Jim Young

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 for the Nov. 8 election and is 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 stoked controversy on Tuesday by suggesting that Barack Obama, the first African-American U.S. president, was “raised white,” and Ohio Governor 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.

Trump took to Twitter as polls opened on Tuesday night to encourage voters to turn out and cast ballots for him, taking a jab at Cruz, whom he has continually described as dishonest.

“Make sure you get on the Trump line and are not misled by the Cruz people,” he wrote. “They are bad! BE CAREFUL.”

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Hoping to gain an edge in Nevada, Cruz spent time engaging rural voters and far-right conservatives. Rubio, the son of former casino workers who spent six years in Nevada as an adolescent, played 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.”

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.

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

Strategists said Rubio was benefiting from the withdrawal 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 since then, including U.S. Senator Dean Heller and Nevada Lieutenant Governor Mark Hutchison.

He touted those gains at a campaign rally in Michigan on Tuesday, saying he was “proud” of supporters who had made the switch to him after Bush’s exit.

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.

The firing came amid intense criticism of the Cruz campaign for unethical behavior from both Trump and Rubio. Trump, known for his blistering attacks against his rivals, continued to focus his venom on Cruz on Tuesday, writing on Twitter that he “lies like a dog.”

Cruz aimed to quiet one of Trump’s most common attacks - that he isn’t eligible to run for president because he was born in Canada - on Tuesday when he asked a federal court in Houston to throw out a class-action lawsuit questioning his eligibility.