The Mitt Romney campaign was suffering an acute bout of electoral vertigo yesterday after the leaking of a video showing the candidate disdaining almost half the country as lay-about loafers he cannot "worry about" and writing off the search for Middle East peace as a fool's errand.

Coming at the end of a difficult stretch that has seen President Barack Obama pulling away in some polls, the video clips, first released by the left-leaning magazine Mother Jones, triggered an uproar that could inflict long-lasting damage on Mr Romney's presidential hopes.

He apparently made the remarks at a $50,000-a-plate dinner at a donor's home in Boca Raton, Florida, in May. A 70-minute video made surreptitiously at the event was passed to Mother Jones; the middle man in the transaction was a grandson of former President Jimmy Carter.

At one moment, Mr Romney is heard to gripe: "There are 47 per cent of the people who will vote for the President no matter what. There are 47 per cent who are with him, who are dependent upon government, who believe that they are victims, who believe that government has a responsibility to care for them, who believe that they are entitled to health care, to food, to housing, to you name it."

The comments veered into even more perilous territory perhaps when Mr Romney explained that 47 per cent of Americans pay no federal income tax. It was his job, he averred bluntly, "not to worry about those people. I'll never convince them they should take personal responsibility and care for their lives".

While the assertion that nearly half of adult Americans do not pay federal income tax may be broadly correct, the full picture is more complicated. Many of those people pay other forms of taxes, including payroll, sales and property taxes. Some are excused from federal income tax because they are elderly and draw benefits from programmes into which they have paid taxes all their lives. And many may be Republicans.

No time was wasted by the Obama camp to use the clips to paint their opponent once again as cold and out of touch with ordinary Americans. "When you are President of the United States, you are President of all the people, not just the people who voted for you," said Jay Carney, the President's spokesman.

"The man who spoke these words – who demonstrates such disgust and disdain for half of our fellow Americans – is the other side's choice for President of the United States," a mocking fundraising email sent last night to supporters of Mr Obama proclaimed. "He wants to lead our country."

The comments on foreign policy may also spell trouble for the former governor of Massachusetts.

Most notable was a suggestion that Middle East peace was unattainable because the Palestinians are "committed to the destruction and elimination of Israel".

Dealing with the fall-out from the video may be the biggest challenge yet faced by the Romney campaign. A statement was put out soon after the first video footage became public and then, with only 15 minutes' warning, reporters travelling with him in California were summoned to a 10pm press conference.

"It's not elegantly stated, let me put it that way," he said at the press conference in reference to the 47-per-cent remark.

"I was speaking off the cuff in response to a question." Speaking on Fox News last night Mr Romney did not back down and asserted he opposed redistribution of wealth by government calling it a "foreign concept".

While Mr Romney may have stumbled by conflating those receiving benefits or paying no tax with people who support Mr Obama – and by insulting them – the issue he raises is at the core of the ideological clash in this race, with Republicans arguing that, under Democrats, government is smothering America.

What Mitt said...

On 'the 47 per cent' There are 47 per cent of the people who vote for the President no matter what… who are dependent upon government, who believe that they are victims, who believe the government has a responsibility to care for them, who believe that they are entitled to health care, to food, to housing, to you-name-it… These are people who pay no income tax... So our message of low taxes doesn't connect… And so my job is not to worry about those people. I'll never convince them they should take responsibility and care for their lives...