Mitt Romney, the presumptive Republican candidate in the United States presidential election, has opened up a convincing lead in the money stakes against President Barack Obama, prompting the Obama campaign to accuse the multi-millionaire former Governor of trying to buy the White House.

Romney and the Republican Committee raised more money than Obama for the second straight month in June, bringing in US$35 million ($44 million) more than the President's re-election campaign of US$71 million.

While the Obama campaign had expected the opposition spike, the President's campaign spokesmen turned their fire on the so-called Super PAC supporters whose donations have no ceiling under a Supreme Court ruling.

"You've got a few very wealthy people lining up trying to purchase the White House for Mr Romney," said David Plouffe, the White House senior adviser.


But despite the widening fundraising gap, which will enable the Republican candidate to pour money into TV ads in the swing states critical for the election result, the former Massachusetts Governor is struggling to open up a similar lead in the opinion polls.

A Reuters/IPSOS survey yesterday predicted that Obama would coast to victory in the November election by six points, putting him on 49 per cent compared with 43 per cent for Romney. Other polls this week showed a continuing dead heat between the candidates.

Romney's campaign has been plagued by missteps after a landmark Supreme Court ruling last month that upheld Obama's core healthcare reform while deciding that it was a tax. After a senior Romney adviser went on television to disagree with the court decision, Romney intervened to state that the court had the final word and that the reform - which he had implemented on a statewide basis in Massachusetts - was a tax.

At the end of last week he shook up his communications staff to get them back on message, after the Wall Street Journal criticised the campaign's "insular staff and strategy that are slowly squandering a historic opportunity". His foreign policy advisers have been accused of in-fighting as he prepares for an overseas tour this month.

Romney's campaign has failed to inspire the mainstream Republican Party, and the party's conservative base has embraced the Mormon candidate even less. The House Speaker, John Boehner, mentioned at a fundraiser that "the American people probably aren't going to fall in love with Mitt Romney". Boehner went on to point out, rightly, that the election would be a referendum on Obama's handling of the economy. After a media storm over his remarks about Romney, Boehner, too, was back on message yesterday, saying that voters would be "enthusiastic" about voting for the candidate.

On the campaign trail, Obama is throwing all his effort into the swing states - most recently Ohio and Iowa - pitching to the middle class. He has urged Congress to extend Bush-era tax cuts for those earning less than US$250,000 a year.

At the same time, his attack ads have been going after Romney's alleged "hidden" money in overseas accounts, accusing him of incomplete financial disclosures. One ad, which ran in Virginia and Ohio, is entitled "Swiss bank accounts", and aimed at reinforcing the impression that the wealthy Romney is out of touch with the average voter.

"I have paid my taxes as due," Romney hit back on Fox News yesterday. "I have also disclosed through all of the requirements of the Government, every asset which I own."

Clearly on the back foot, Romney also responded in Colorado to other criticism from the Obama ads that his much-touted business experience, at the private equity firm Bain Capital, had created jobs outside the US. It is Obama who is the "outsourcer in chief," Romney protested.

According to the Washington Post, Obama had spent more than US$91 million on TV adverts in eight swing states by July 6, compared with US$23 million spent by the Romney campaign.

The ads air during news bulletins, sit-coms and sports broadcasts. It remains to be seen whether the adverts will really influence voters who normally pay little attention to politics, or whether they could be a massive turn-off.