Here comes the next GOP primary contest ...

Nevada Republicans are headed to caucuses on Tuesday evening to cast a potentially decisive vote in the Republican presidential-nominating process.

Though Republican frontrunner Donald Trump led in recent surveys of the state, Nevada is notoriously difficult to poll, making the contest more unpredictable.

Sens. Marco Rubio and Ted Cruz currently trail Trump in the state, but they are counting on superior campaign infrastructure to undercut the real-estate mogul's broad base of support.

At a glance, the Nevada caucuses appear to be a three-way race between Trump, Rubio, and Cruz.

Ohio Gov. John Kasich, who placed second in the New Hampshire primary, hasn't given much time to Nevada and spent his Tuesday across the country in Georgia. Retired neurosurgeon Ben Carson is also still soldiering on, despite finishing at the bottom of the pack in last weekend's primary in South Carolina.

In an Associated Press report published earlier on Tuesday, Rubio said that he didn't know how the night would end.

"I think it's the most unpredictable of all the races we've had so far. You go in really knowing less about this than any other election," Rubio said. "We'll see."

Early registration showed that voter turnout would likely be far higher than previous years' Republican presidential primaries. This could be a boon for Trump, who tends to poll better among the broader Republican electorate than core groups of historically diligent primary voters.

Jon Ralston, one of the most prominent reporters in Nevada, predicted that high voter turnout could also result in a long night before the caucuses' winner is determined:

Though the presidential field has winnowed significantly over the last several weeks, Cruz, Rubio, and Trump have traded increasingly sharp blows on the campaign trail. Cruz and Trump have been locked in a particularly bitter rhetorical battle in recent weeks.

Earlier on Tuesday, Trump called Cruz a liar and even compared him to a weak baby.

"This guy Ted Cruz is the single biggest liar I have ever dealt with in my life," Trump told his supporters at a rally.

"He's like a little baby. Soft, weak, little baby by comparison. But for lying, he's the best I've ever seen," he added.

For his part, Cruz has attempted to rally anti-Trump supporters by asserting that he is the only candidate who can defeat the businessman.

"We are the only campaign that has beaten and can beat Donald Trump. That's why Donald relentlessly attacks us and ignores all the other candidates," Cruz said last weekend.