Cracks in the awkward marriage between Donald Trump and Republican leaders grew wider on Sunday, as Senate stalwarts recoiled from their presumptive presidential nominee, his campaign moved in for a closer embrace, and the businessman fell freely in polls after a weekend romp in Scotland.

Dark days for Republicans as Never Trump faction eyes one last end-around Read more

The most conspicuous silence in the room came from Senate majority leader Mitch McConnell, who repeatedly refused to say whether he thought Trump was qualified to be president.

“Look, I’ll leave that to the American people to decide,” he told ABC’s This Week. “It’s a long time until November. And the burden, obviously, will be on him to convince people that he can handle this job.”

McConnell admitted Trump’s campaign has shown clear signs of disarray a month after the nomination was secured: its campaign manager was fired and it was revealed it had only $1.3m in cash and had spent hundreds of thousands of dollars at Trump’s Florida resort and on hats. The Democratic presumptive nominee, Hillary Clinton, in contrast reported more than $42.5m raised.

The architect of Republican victories in the Senate, McConnell wrote in a new memoir that the three most important words in politics are “cash on hand”. On Sunday, he said Trump could not win with such weak fundraising.

He needs to catch up and catch up fast. Where the money comes from … it doesn’t really make all that much difference Mitch McConnell

“He needs to catch up and catch up fast,” he said. “Where the money comes from, whether it comes out of his own pocket or from others, it doesn’t really make all that much difference. But he’s going to have to have way more than he has now in order to run the kind of campaign he needs to win.”

One of the most powerful members of Congress, McConnell has acted as a diplomat between the candidate and lifelong Republicans horrified by Trump’s disregard for facts, support from racist groups and wide deviations from central conservative proposals.

This week, two top advisers to George W Bush endorsed Hillary Clinton, and prominent conservative writer George Will unregistered with the party. One Republican senator, Mark Kirk of Illinois, has started running an anti-Trump ad to support his re-election campaign.

McConnell tried to reassure Republicans, saying the party’s platform would be written by trusted members of the party – an implicit rebuke of many of Trump’s proposals.

The Senate leader declined to specify where his allies would clash with Trump, but party leaders have spoken out against the candidate’s calls for mass deportations, a ban on Muslim travelers and the tearing up of free-trade agreements.

“Our nominee may not agree with every single one of those,” McConnell said, “but the Republican party will remain America’s conservative party.”

Nor would McConnell broach two new polls that show Clinton ahead of Trump by healthy margins. In a Wall Street Journal/NBC poll, Clinton led by 46% to 41%. In a Washington Post/ABC poll, she led 51% to 39%.

That poll also found that 64% of Americans surveyed felt Trump was unqualified, and that his support among Republicans has declined since he secured the nomination. Averages show Clinton with an almost seven-point lead.

“I think there’s no question that he’s made a number of mistakes over the last few weeks,” McConnell said. “I think they’re beginning to right the ship.”

Senator Marco Rubio, who recently announced a re-election bid, also shied away from Trump, whom he called “a con man” during his own failed presidential campaign. Rubio has said he will vote for Trump, but on Sunday rejected several of the candidate’s ideas, including the ban on Muslim immigration and deportation of migrants.

“You can’t round up and deport 11 million people. There are people that need to be deported. Criminals need to be deported,” he told CBS’s Face the Nation. “The American people wouldn’t stand for it once they saw what it would take to make that happen.”

Rubio also dismissed the idea that he might join Trump’s ticket as a vice-presidential candidate, saying: “The differences in policies that me and Donald have had are too big for something like that to work.”

Paul Manafort, the leader of Trump’s campaign after Monday’s firing of Corey Lewandowski, has in recent weeks moved to stifle what dissent remains in the party, and to further wed its workers to the businessman’s thinly staffed operation.

“Our campaign is, frankly, getting organized,” he told NBC’s Meet the Press. “It’s all in words I guess, but we are fully now integrated with the Republican National Committee.”

Trump is reportedly relying heavily on the Republican National Committee (RNC) to fundraise for him, even though major donors have expressed repulsion, some publicly and others in private to the Guardian and other news organizations.

Trump’s first fundraising email, sent this week, went to the spam box of 60% of recipients, according to email tracking firm Return Path. Trump’s campaign says it raised $3.3m off the email.

Manafort said the campaign would make “major announcements” this week and was “organized in all 16 states that we’re going to be targeting”.

He also refused to acknowledge the disadvantages that McConnell recognized. The Trump campaign reported about 70 people on staff, for instance, while Clinton reported almost 700.

“We have hundreds, we have actually thousands of people in the battleground states, political organizers who are now in place,” Manafort insisted, including in his count party staffers. “We’re confident that we’re not behind the Clinton campaign.”

Those party workers are not technically part of the campaign and may be more concerned about local senate or house races. Many are of uncertain loyalty to the Trump movement.

Facebook Twitter Pinterest Mitch McConnell speaks in Washington. Photograph: Molly Riley/AFP/Getty Images

Last week House speaker Paul Ryan, the most powerful Republican in Congress, almost encouraged members of his party to rebel against Trump saying: “I am not going to tell somebody to go against their conscience.”

Since then a small group of Republican delegates have tried, albeit with little hope, to create a “conscience clause” that would let them vote for someone besides Trump.

RNC chairman Reince Priebus has tried to counter them with people loyal to the party, if not the candidate. Like McConnell and Ryan, Priebus has tried to broker a truce between Republicans and their presumptive nominee, and like them he has put on a brave face.

“I haven’t started pouring Baileys in my cereal yet,” he joked earlier this year, to the New York Times.

Trump spent the weekend in Scotland, where he guided reporters around in small ATVs while he played 18 holes of golf. He was largely unperturbed by the chaos roiling Britain in the wake of Thursday’s vote to leave the European Union, and said he did not want to talk about advice from foreign policy experts.

“Honestly, most of them are no good,” he told NBC. “Let’s go to the 14th.”