Donald Trump’s campaign and some of his allies are rushing to tamp down the storm of opprobrium and handwringing ignited by his refusal, at the final presidential debate on Wednesday, to say he would accept the result of the election in November.

However, a growing number of Republicans also voiced dismay about his remarks on the debate stage in Las Vegas. The Republican National Committee, RNC, found itself in the extraordinary position of breaking from its own candidate on the issue.

Asked by the debate moderator, Chris Wallace, to state clearly that he would accept whatever the results are on election night, Mr Trump demurred saying he would decide only when the time comes, adding: “I’ll keep you in suspense.”

His opponent, Hillary Clinton, said she was “horrified” by the response. “That is not the way our democracy works. We've been around for 240 years,” she said. “We've had free and fair elections. We've accepted the outcomes when we may not have liked them. And that is what must be expected of anyone standing on a debate stage during a general election.”

Her allies were pressing the same point home on Thursday. Invoking the notion that the peaceful transition of power has been at the heart of American democracy since the nation’s founding, Tim Kaine, her running mate, said Mr Trump “is trying to pull the central pillar down”.

Senator John McCain, the Republican nominee in 2008, reminded Mr Trump of how he accepted defeat by Barack Obama. 'I didn't like the outcome of the 2008 election," he said. "But I had a duty to concede, and I did so without reluctance. A concession isn't just an exercise in graciousness. It is an act of respect for the will of the American people, a respect that is every American leader's first responsibility."

Staying with the theme that the election is being stacked against him, Mr Trump on Thursday morning issued a tweet alleging that Ms Clinton had been handed the debate questions early. “Why didn't Hillary Clinton announce that she was inappropriately given the debate questions – she secretly used them! Crooked Hillary,” he said

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Kellyanne Conway, the Trump campaign manager, was once again left to massage words uttered by her boss into something vaguely palatable. In this instance, likening his refusal to promise now to accept the election outcome with the drama in 2000 when Al Gore first conceded and then withdrew his concession when the key Florida result fell into doubt.

Mr Trump “respects the principles of democracy”, she attempted on ABC News. “It’s just that he can’t say what’s going to happen if the election is very tight, if it’s just a few votes here and there, as was the case in 2000, if one state like Florida is less than 600 votes, as was the case then …We just don’t know what will happen.”

“I just think Donald Trump is also putting people on notice that if there are irregularities, if there’s voter fraud, if there’s large-scale malfeasance that's committed, that he's not just going not to want to investigate that, but we have to see what happens,” Ms Conway also said.

Historically, there is very little evidence of voter fraud in the United States on any kind of scale that has altered the outcome of an election. Even claims that John F Kennedy somehow stole the 1960 election with fake votes in Chicago have been somewhat debunked over time.

Meanwhile, any expectation that this will be a very tight election is becoming less and less convincing. If Mr Trump needed a knockout blow on the stage on Wednesday it is because Ms Clinton has been widening her national lead steadily since the first of their three debates in September. Additionally, his standing in several swing states has also been slipping.

Social media meanwhile was set alight by two other statements from Mr Trump on the debate stage. The one was when he interrupted Ms Clinton as she was attempting to talk about the future of Obamacare saying, “such a nasty woman”, the other was his reference to “bad hombres” living in the US when he was discussing immigration and his deportation plans. Thus the candidate managed to demonstrate racism and sexism in two short takes.

A CNN/ORC snap poll said 52 per cent of viewers thought Ms Clinton won the debate and 39 per cent said Mr Trump, a former reality TV star, was the victor. On Twitter, meanwhile, President Barack Obama said his former Secretary of State had scored an “Outstanding 3 for 3 debate sweep.” Earlier this week, Mr Obama lacerated Mr Trump for suggesting even before the debate that the election was rigged saying he “was whining before the game’s even over”.

Among Republicans appearing to mourn Mr Trump’s debate performance was leading conservative commentator Laura Ingraham, who tweeted: “He should have said he would accept the results of the election. There is no other option unless we're in a recount again.”

Meanwhile the alarm bells about the negative impact that Mr Trump could have on other Republicans running for Congress and state houses were ringing louder than ever on Thursday. At stake in particular is control of the US Senate where Republicans are defending their majority. Senate races in Nevada, Florida, New Hampshire and Missouri appear to have tightened.

“The biggest loser tonight was not Trump, the presidential race is over,” Robert Blizzard, a GOP pollster who is working on a number of congressional races, told Politico. “Instead, down-ticket Republicans lost tonight – they needed some help and got absolutely none.”

If many Republicans were nursing frustration it was because for the first 30 minutes or so of the debate, Mr Trump appeared to be showing a new level of discipline, limiting himself to challenging Ms Clinton on policy issues, including immigration, trade and abortion. In those moments he was surely close to showing the mien of someone who could be president.