Offshore accounts hand Obama an easy hit in row over Romney's riches

President tries to move on from economy with call to end tax cuts

Mitt Romney: He has held investments in tax havens such as Bermuda and Switzerland (Getty Images)

As President Barack Obama's re-election campaign pushes to cast Mitt Romney, the Republican presidential nominee, as a champagne candidate bent on protecting the rich, Mr Obama yesterday renewed his call on the US Congress to end Bush-era tax cuts for wealthier households while extending them for middle-class Americans.

The move, announced by Mr Obama in the White House, came as his campaign has stepped up pressure on Mr Romney to explain past holdings in overseas tax havens such as Switzerland and Bermuda.

Just days after the release of yet another round of disappointing employment numbers, the Obama campaign is straining to change the subject. It wants to drive home its claim that Mr Romney and his conservative allies want to favour the top earners at the expense of the middle class.

The White House also means to tar members of Mr Romney's party in the Congress in the same way. The tax cuts, first enacted on President George Bush's watch, are – for now – set to expire at the end of this year. The Republican leadership is expected to offer an opposing plan that would extend them for mid-income and high-income earners.

"Many members of the other party believe that prosperity comes from the top down. I disagree," President Obama said. Under his proposal, the tax cuts would be eliminated at year end for any household earning $250,000 or more. "It's time to let the tax cuts for the wealthiest Americans, folks like myself, to expire," he said.

While supporters of Mr Obama will be glad to see him going on the offensive, the chances of agreement on any of the pending tax issues on Capitol Hill are less than remote between now and the election. If anything, the President's words will only deepen the sense of polarisation in Washington. Analysts complain that that gridlock and the lingering legislative uncertainty are retardants to recovery.

Money now colours the race at every level. It emerged yesterday that the president raised $71m for his campaign in June while Mr Romney raked in $106m. The personal tax affairs of Mr Romney continue meanwhile to stalk him, with new questions being raised both in the media and by the Obama camp about holdings he once held in overseas havens. These emerged when the candidate in January published his 2010 tax return and an estimate for 2011. Now Democrats are demanding he make public his returns going back more than two decades.

Among old holdings now under scrutiny are a bank account in Switzerland, investments in the Cayman Islands and a small company in Bermuda called Sankaty High Yield Asset Investors Ltd that was transferred to Ann Romney when Mr Romney became Governor of Massachusetts in 2003.

While not accusing him directly of tax evasion, some Democrats are questioning why he would move his earnings overseas. "You either get a Swiss bank account to conceal what you are doing or you believe the Swiss franc is stronger than the American dollar," Illinois Senator Dick Durbin said.

Romney aides have called the attacks "unseemly and disgusting". But journalist and tax haven expert Nicholas Shaxson, who wrote an exposé about Mr Romney's overseas holdings in the current issue of Vanity Fair magazine, said yesterday that it remains important for the authorities to determine once and for all if the way Mr Romney moved his money around in the past was "strictly legal or not".

"There is a question mark over that," he said. "It is the campaign mantra and Mitt Romney's mantra that it is completely legal and there's nothing wrong with it. That statement needs questioning further."