Welcome to a Republican 'rightmare': Donald Trump's presence in the US presidential election race could hand the White House to Hillary Clinton

Out of America: If he stays much longer, then the GOP brand that party elders are trying so hard to rebuild risks a real beating

Loose cannon? Every rebuff seems to make Donald Trump more popular (AP)

In case you hadn’t noticed, he’s back. Vainer, more bombastic and more preposterous than ever, Donald Trump is running for president again. And the Republican Party to which (for now at least) he belongs, is scared out of its wits.

We have, of course, been here before. In 2000, Trump was a candidate of the Reform Party founded by Ross Perot. In three other elections he’s floated the idea of competing in the Republican primaries – most recently in 2012, when the mere possibility of a Trump bid for the White House saw him briefly top the polls, admittedly against a weak Republican field. In the end, he decided not to run. This time, however, he is running, against one of the biggest and most qualified fields in memory. And guess what? He’s leading the pack again.

An Economist/YouGov poll on Friday had him at 15 per cent among registered Republican voters, four points clear of Jeb Bush, and well ahead of the other two favourites for the nomination, Marco Rubio and Scott Walker, not to mention the likes of Chris Christie, Rand Paul, Rick Perry et al.

Now, this is the silly season for US presidential politics, almost seven months before the Iowa caucuses kick off the primary season. Cast your mind back to the same moment of the last election cycle, in high summer 2011. Leading the Republican pack was the pizza magnate Herman Cain (he of “I don’t know who’s president of Ubeki-beki-beki-beki-stan-stan”), followed by Michele Bachmann, fire-breathing queen of the Tea Party. Both candidacies ultimately sank without trace.

Fast forward to 2016, and Trump is their natural successor, an endless source of quotes and headlines, ideal political entertainment as the dog days beckon. Except, that is, if you’re part of the Republican establishment. There, the conventional wisdom – or perhaps wishful thinking – is that Trump will fizzle like Cain and Bachmann, as soon as chilly autumn signals a return to political common sense. But Trump says he’ll be around, in one guise or another, for a good deal longer. If so, then the GOP brand that party elders are trying so hard to rebuild risks a real beating.

Those fears began the very day Trump formally announced his candidacy at his eponymous Tower in New York a month ago. His focus was on immigration, the most sensitive single issue for Republicans as they seek to improve on Mitt Romney’s dismal showing in 2012, when he won just 27 per cent of the Hispanic vote, a failure that guaranteed his defeat.

“The Donald”, though, was having none of it. “When Mexico sends its people, they’re not sending their best…. They’re sending people that have lots of problems, and they’re bringing those problems with them. They’re bringing drugs. They’re bringing crime. They’re rapists.... And some, I assume,” he added with withering condescension, “are good people.”

Republican grandees were aghast, the immigrant community was in uproar, and Democrats could not contain their glee – especially because Trump, far from back-pedalling, doubled down on his claims. Every illegal immigrant was a “potential rapist” he later declared on CNN, demanding that Mexico build a wall to keep them out. Naturally, he professed love for Mexico. “This isn’t just about Mexicans. I’m talking about people that are from all over that are killers and rapists and they’re coming into this country.”

Predictably, many doing business with the great self-promoter, among them NBC, Macy’s and the Professional Golfers’ Association, have fled for the exits. José Andrés, the Spanish super-star chef, has cancelled plans for a restaurant in the de luxe hotel that Trump is building here in Washington. But every rebuff, it seems, only makes Trump more popular – even the revelation that construction workers at the hotel are mostly immigrants, some of them presumably illegals.

Real estate mogul and TV personality Donald Trump announced his campaign for the 2016 Republican presidential nomination last month (Getty) (Getty Images)

And the megalomania only grows. The other day, Reince Priebus, the Republican party chairman, called Trump, asking him, we were told, to “cool it”. The property mogul quickly put Priebus in his place. It was a “congratulatory call,” he told The Washington Post: “He’s going to lecture me? Give me a break.” Giant egos do not slip quietly into the good night.

But some interested parties have been notably quiet. I refer to Trump’s competitors for the nomination. Yes, a few, notably Bush and Rubio, have chastised him, but belatedly and relatively gently. The silence speaks volumes about the Republicans’ dilemma. Detest Trump if you will, but on immigration he’s telling the party’s core electorate – older white voters, this time more important than ever given the party’s problems with blacks, Hispanics and other minorities – just what it wants to hear.

Not only on immigration. If you’re fed up with Obama’s caution in the Middle East, how sweet “the Donald” must sound. A President Trump would “bomb the hell” out of Iraq’s oilfields to strike at Islamic State. As for US troops on the ground, forget it: “You won’t need ’em by the time I’m done.”

This confronts Priebus and the establishment with a double nightmare. The first is Trump’s participation in the first candidates’ debate on 6 August. Given that he easily qualifies among the top 10 candidates measured by the polls, he can hardly be denied a spot. He might make an idiot of himself. Equally likely, though, he’ll upstage everyone with his soundbites, handing yet more election ammunition to the Democrats.

The second nightmare is even worse. What if Trump drops out, only to run as a third-party candidate, just as Perot, another nationalist billionaire, did in 1992? Many Republicans blame Perot for stealing votes from George H W Bush and handing victory to Bill Clinton. Speaking to the Post last week, Trump deliberately kept the third-party option open and, with it, the prospect of throwing another winnable election to another Clinton. Republican nightmares, even in the political silly season, don’t come much worse.