Nevada Republican caucus: Donald Trump supporters approve of straight-talking approach as he targets Ted Cruz

Mr Cruz's demands that his spokesman resigns over a fake video has done little to dissuade Mr Trump from depicting the Texas Senator as a slippery customer

Republican presidential candidate Donald Trump speaks at a rally in Las Vegas (Getty Images)

On the verge of another likely victory in the Nevada Republican caucuses, Donald Trump said of a heckler at a rally in Las Vegas that he would like to “punch him in the face”.

In any other election, such an outburst might have brought the candidate’s campaign to an ignominious end, but at Mr Trump’s event it drew only laughter and loud applause. The rally at the South Point Arena was attended by a capacity crowd of around 8,000, and touted by its organisers as the biggest political gathering in Nevada history.

The “punch” comment was of a piece with Mr Trump’s belligerent rhetoric, which in recent days has been directed largely at his conservative rival, Texas Senator Ted Cruz. Mr Cruz’s previously ultra-disciplined campaign made a misstep on Sunday, when spokesman Rick Tyler tweeted a video of Marco Rubio apparently mocking the Bible.

The video turned out to be false, and Mr Cruz has demanded Mr Tyler’s resignation. Yet his dismissal has done little to dissuade Mr Trump from depicting the Texas Senator as a slippery customer. “Cruz lies more than any human being I’ve ever dealt with... [he’s] sick,” Mr Trump said at his rally, tweeting earlier that Mr Cruz had been “disloyal” to the “very capable” Mr Tyler.

At the rally, Mr Trump’s supporters were invigorated by what they saw as his straight-talking approach. Corrections officer Erika Von Tagen, 30, said his pugnacity was precisely his appeal. “We need to be strong in the eyes of our enemies,” she said. “He’s a good face for this nation.”

Retired stockbroker Joe Russi, 52, said he backed Mr Trump in large part due to his business credentials. “It’s not Democrats and Republicans anymore, it’s businessmen and socialists,” he said. “We need someone who can handle the country and the debt we have as a businessman.”

At his own rally in Las Vegas this morning, hours before the caucuses, Florida Senator Marco Rubio claimed he was the one remaining candidate capable of uniting Republicans to beat Democrat Hillary Clinton in November’s general election. “It can’t just be about electing the loudest person in the room,” he insisted, yet in Nevada neither he nor Mr Cruz has managed to draw crowds half as large as the bombastic front-runner.

Mr Trump and Mr Rubio both have personal ties to the Silver State. Mr Trump owns 50 per cent of the 64-storey Trump International Hotel, yards from the Las Vegas Strip. Mr Rubio, by contrast, spent part of his childhood in Las Vegas, where his father worked as a casino barman and his mother as a hotel maid. Portraying himself as a champion of the city’s low-income hospitality workers, Mr Rubio promised to spread the conservative message “to people who are living the way I grew up.”

Yet the immigrant workers who make up much of the city’s labour force are unlikely to be a significant voting presence at the GOP caucuses. Indeed, the crowds at the three major candidates’ Las Vegas events were all overwhelmingly white.