Donald Trump will go to Washington in bid to smother mutiny within Republican Party

Donald Trump will blitz top Republicans in Washington as soon as next week with a mix of courtship and cajoling in hopes of bringing those voicing doubts about his candidacy into line.

As Mr Trump turns his attention away from the primary contest towards battling Hillary Clinton, his likely Democrat rival in November, the horror that his becoming the presumptive nominee has elicited in some quarters of his own party threatens gravely to damage him going forward.

He made the plan even before the speaker of the House, Paul Ryan, dropped a fresh grenade on Thursday declaring that he for now remains unable to endorse Mr Trump as his party's nominee-apparent. "I think what a lot of Republicans want to see is that we have a standard bearer that bears our standards," Mr Ryan said in an interview with CNN.

In the latest blow, recordings obtained by Politico showed Senator John McCain, the nominee in 2008, suggesting that his chances of being re-elected in his own state of Arizona this year would be severely damaged if Mr Trump were the nominee. Meanwhile, aides close to both former Bush presidents, George HW and George W, have said neither will be endorsing Mr Trump.

Mitt Romney, the party’s 2012 nominee, announced that he will not attend the party’s national convention in July in Cleveland where Mr Trump will be officially crowned, an extraordinary departure from normal party etiquette that can only be interpreted as a direct snub.

Exerting his authority over the Republican family is thus becoming paramount for Mr Trump. And while the party apparatus is doing its best – the Republican National Committee reportedly has told all its staffers that if they can’t bring themselves to love him they should clear their desks by week’s end – eliminating every pool of enmity towards him may prove a difficult task.

Closing the fissures that his candidacy has opened – thanks largely to his more extreme proposals, for instance, to build a wall along the Mexican border, deport all 11 million people who live in the country without papers and stop Muslims from coming in at all – would also send a vital message to traditional Republican donors who may be hesitating about him.

“If Donald Trump is at the top of the ticket, here in Arizona, with more than 30 per cent of the vote being the Hispanic vote, no doubt that this may be the race of my life,” McCain said a fundraiser at the state held before Mr Trump won Indiana this week and his two last rivals dropped out. “If you listen or watch Hispanic media in the state and in the country, you will see that it is all anti-Trump. The Hispanic community is roused and angry in a way that I've never seen in 30 years.”

The Washington trip is expected to happen sometime before the middle of this month with Senator Jeff Sessions also from Alabama, a longtime Trump ally, expected to broker meetings between him and different factions of the party, Politico said.

Disenchanted donors include Bill Achtmeyer, the founder of consulting firm Parthenon Group, in Boston, who has donated heavily to Republicans in the past. Yesterday he told Reuters he was considering switching his allegiance to Ms Clinton. "If she is able to move to the centre and think as creatively and thoughtfully as her husband did ... boy, I would have a very hard time, based on what I know today, not voting for Hillary versus what Trump is espousing,” he said.

Mr Trump is also moving on several other fronts to cover the cracks in his credibility. On economic policy, he said on Thursday that he would be unlikely as president to keep Janet Yellen as leader of the Federal Reserve and would attempt to renegotiate some of America’s debt to find lower rates and use the money that would be saved on infrastructure projects.

He also confirmed his intention to behave more like a traditional candidate on the fundraising front, hiring Steven Mnuchin, the chief executive of Dune Capital Management, a private investment firm, as his financial chair who will be responsible for raising outside funds for his campaign going forward. Mr Trump has hitherto boasted that his campaign has been mostly self-funded.

If he fails to allay the party’s unease, Mr Trump may find that many big-hitters of the Republican Party skip the Cleveland convention in July. That may also be true of corporate interests that might normally be on the hook to help pay for it. Microsoft recently announced it was pulling out of being sponsor this year, though before it became clear that Mr Trump would be the nominee.

While Mr Romney’s absence will be a stark reminder of the divisiveness of Mr Trump, it will surprise almost no one given the attempts the former Massachusetts Governor made this spring to derail the Trump train, notably with a witheringly critical speech in Salt Lake City in March when he asserted that the candidate was “playing Americans for suckers”.

Mr Trump, for one, offered an “am I bothered?” response to the news that Mr Romney would be a no-show. “I don’t care,” he told The Washington Post. “He can be there if he wants.”