Republican Party faces crisis as Trump heads for Super Tuesday victory

Donald Trump appears poised for sweeping victories on “ Super Tuesday ” that would effectively anoint him the Republicans’ presumptive nominee, leaving the polarised conservative party in the throes of an existential crisis.

Related: Trump rally turns violent: photographer thrown to ground amid protests

As Republican primaries or caucuses open in 12 states, with the New York billionaire well placed sweep them all save Texas, where Ted Cruz looks set to win on home turf. On Monday one national CNN opinion poll of Republican voters put him at 49%, more than all his opponents combined.

The dawning reality of Trump – an entrepreneur and reality TV show host who began the campaign viewed by many as something of a joke – as the party favourite has left senior Republicans scrambling to either destroy or jump aboard his populist bandwagon .

Although New Jersey governor Chris Christie and Alabama senator Jeff Sessions have endorsed him in recent days, many other governors and senators have remained silent or actively denounced him as unfit for the presidency or to take on Democrat Hillary Clinton.

Mitt Romney, the Republican nominee defeated in 2012, has launched a series of attacks, while Nebraska senator Ben Sasse has raised the prospect of backing a third-party option.

With Trump having won three of four early primary contests, the panic was evident ahead of Super Tuesday, the biggest single-day delegate haul of the year. His rivals sped from state to state in a frantic bid to prevent what many now regard as the inevitable outcome.

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Marcio Rubio, the party establishment’s last best hope, attacked the frontrunner on everything from the now-defunct Trump University to the outsourcing of jobs to manufacture Trump’s wide range of namesake products.

“If he was interested in bringing back American jobs, he could start this very morning by announcing that every product that says Donald Trump on it will be made in America,” Rubio said at a morning rally in Knoxville, Tennessee. “I challenge him to do that.”

At a subsequent event in Conway, Arkansas, Rubio turned to Trump’s stance on immigration and his infamous promises to build a wall on the Mexican border. Trump, who has made his tough approach to immigration the cornerstone of his campaign, has not always held such firm views on the issue, Rubio said, citing a report that the reality TV star privately expressed a much softer position to the New York Times .

Although the conversation with the Times editorial board was off the record, Rubio called on Trump to grant permission to the paper to release the audio of the interview “so we can see exactly what it is he truly believes”.

Romney also tweeted that Trump should authorize the New York Times to release the transcript, asking: “What is he hiding?”

Interviewed on Fox News, Trump sought to dismiss the issue. “I call it the failing New York Times,” he said. “It is doing so badly, it’s dying. We had a board meeting, it was off the record, all of a sudden they leak it, it’s all over the place.”

On immigration, he went on: “It is negotiable; things are negotiable, I’ll be honest with you, I’ll make the wall two feet shorter or something. Everything’s negotiable. Building it? Not negotiable.”

Rubio reiterated his criticism of Trump for failing to denounce the former Ku Klux Klan leader David Duke and the KKK in an interview the day earlier , and then mocked Trump’s claim that the incident was the result of a faulty earpiece.

“You don’t need a good earpiece to hear the words Ku Klux Klan,” Rubio said at an evening rally in Oklahoma City. In what was his biggest applause line of the night, he added: “There is no place for bigotry, for prejudice, for hatred, or for David Duke in the Republican party or conservative movement.”

Rubio’s aggressive posture toward Trump comes as the senator is looking to remain competitive in a race that has so far yielded no victories for his campaign.

With Trump poised for major success on Super Tuesday, Rubio is pinning his hopes on meeting the threshold to secure some delegates in each state, before going into the winner-take-all contests on 15 March – which include his home state of Florida.

Rubio was set to hold a rally in Miami as Tuesday’s results pour in but, in a statement of intent, Trump was also due to spend the evening in Florida, at his Palm Beach resort.

The senator’s new tack has nonetheless invited questions over his willingness to engage in low-brow humour, such as mocking Trump’s face, tan and small hands , while seeking the nation’s highest office. During an interview with Fox News on Monday evening, Rubio defended his campaign as focused primarily on substantive issues – while acknowledging the need to compete with Trump by beating him at his own game.

“Donald Trump has spent a year now insulting virtually everyone,” Rubio said. “I mean very few groups or individuals in America that he hasn’t personally insulted. Every now and then someone like that needs a taste of their own medicine.”

Trump dismissed Rubio as a “lightweight” and said: “He’s very nasty and I think he’s very desperate.”

Texas senator Cruz “is not exactly truthful and I think that’s why I’m doing so well with the evangelicals”, Trump added. “They like the truth.”

Related: Super Tuesday: how the primary calendar's biggest day will unfold

In a packed auditorium on the campus of Houston Baptist University , Cruz, a conservative firebrand whom many in Washington view as even more distasteful than Trump, attacked the real estate mogul’s hiring of hundreds of foreign workers and saying on CNN that “Americans aren’t qualified and aren’t willing to work as waiters and waitresses”.

The room was filled with audible gasps of disdain as Cruz railed against the frontrunner: “Donald Trump does not get to exploit immigration laws and take advantage of American workers and then pretend he’s going to be a champion for American workers.”

Cruz continued to attack Trump being a closet liberal more than eager “to compromise away religious liberty”, adding: “If you’re arguing about marginal tax rates you can reach a compromise on that, but when it comes to the Bill of Rights and the Constitution, we’ve had too many politicians who compromise our rights.”

Texas is the biggest prize on Super Tuesday and allocates 155 delegates. Already a million people have voted absentee, including about 60% of the room that Cruz spoke to on Monday night. Cruz tried to play down expectations, making clear that while “we will do well in the state of Texas, polling doesn’t suggest we are anywhere close to [50% in the state]”.

But Tuesday is also crunch time for the Republican party itself. More delegates are at stake on Super Tuesday than on any other date on the primary calendar and a strong night for Trump could make his nomination almost inevitable.

Several high-profile figures have embraced an anti-Trump social media campaign, using the Twitter hashtag #NeverTrump . An Associated Press survey of Republican senators and governors asked if they would support Trump if he secured the nomination. Just under half of those who responded would not commit to backing him.

On Sunday, Sasse, the first senator to pledge openly not to support Trump in a general election, urged Republicans to consider whether a party led by him would still represent their interests. “If our party is no longer working for the things we believe in, like defending the sanctity of life, stopping Obamacare, protecting the Second Amendment, etc. then people of good conscience should stop supporting that party until it is reformed,” he wrote on Facebook .

Despite the controversies swirling around him, Trump’s momentum appeared unstoppable on Monday. Thousands queued in Valdosta, Georgia, for a glimpse of the candidate, who described himself as “just the messenger” of a social movement.

“My whole life has been money,” he declared. “I want money, I want money. Greed. I was greedy, I want more money, more money. Now they come up, ‘Donald, I’d like to give you $10m for your campaign.’ I go, ‘I don’t want it.’

“It’s hard, because my whole life, I take money, take money. Now, I’m going to be greedy for the United States. I’m going to take and take and take.”

At that the crowd erupted in prolonged cheers, whistles and chants of “USA! USA!”

Sensing he had struck a chord, Trump went on: “We’re going to take, take, take, take. We’re going to become rich again and then we’re going to be great again … We can’t be great unless we’re going to make ourselves rich again.”

Spectator Terry Bradman, 37, an industrial salesman, said it was the biggest event in Valdosta in his lifetime. “We need to support somebody who is going to support America,” he explained. “Trump says what’s on his mind. He doesn’t do political bullshit. He says what the American people have been thinking for years. Everybody’s tired of the Washington politics.”

John Lee, 47, who runs a small business selling “Christian clothes”, was wearing a t-shirt emblazoned with the second amendment. “We want to see The Donald,” he says. “He has common sense. He doesn’t put up with wish-wash; he’s not your standard politician. He stands up for principle and takes care of his people.”

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