In what may mark the start of the 2012 US presidential campaign proper, the Democrats have come out swinging with an attack on Mitt Romney’s connection to Bain Capital, the quickbucks investment vehicle he helped run in the 1990s.

Romney has always maintained that he severed all ties with Bain in 1999, soon after which he was drafted in to plan for the 2002 Winter Olympics in Salt Lake City. He repeated the claim in a 2011 federal disclosures form, which he completed as a first step on the road to presidential nomination.

However, 2001 filings by Romney to the Securities and Exchange Commission described him as sole stockholder of Bain right into 2002, and drawing a six-figure salary from the company. The particular focus of his efforts was a Bain holding called Lifelike — of all things, a maker of fine white china dolls (and the place he met the future Mrs Romney). He also listed himself as a board member of Lifelike for the Massachusetts State Ethics Commission.

The full story was broken by The Boston Globe this week, although parts of it had been revealed earlier by left-leaning magazine Mother Jones. The Obama campaign leapt on it immediately, with a spokesman saying:

“At every turn, at every piece of Mitt Romney’s record or credential, whether it’s Bain, whether it’s his own personal finances, whether it’s who is raising money for him or his time in the Statehouse in Massachusetts, there is an enormous cloud over Mitt Romney’s record because of his penchant for secrecy and not wanting to be transparent and open with the American people.”

The Romney campaign issued an immediate denial, which stonewalled the report. Aside from one small correction, the Globe stood by its report.

The issue is a red hot one, because if the 1999/2002 disjuncture is true, then Romney has either lied repeatedly in public — claiming to have left Bain in ’99, while continuing to receive profits for three years — or he has given false information in an SEC filing.

The latter is a felony, a charge the Obama campaign was throwing around as soon as the news hit the stands. The Romney campaign is rejecting this claim as nonsense, arguing Romney was simply a non-managing owner of Bain Capital over the period, and was not involved in active management.

However the record of involvement with Lifelike and other Bain corporations may contradict that. Should it come down to technicalities, rather than being a clear breach of the rules, then the issue may be no great bonus for the Obama camp. They are however keen to keep Bain Capital in the public mind at all costs, to prevent Romney from portraying himself as a man of the people — rather than as a silvertailed New England asset stripper, whose friends “own NASCAR teams” and who portrays $400,000 in annual speaking fees as “not much money”.

Beyond the Bain accusations, the Obama campaign has another target: to force Romney to make a full disclosure of years of tax returns, which he has so far refused to do. The returns would reveal not only the extent of Romney’s wealth — reported to be $300m — but his extensive network of companies, portfolios and holdings, some of them connected to outsourcing, downsizing and asset stripping.

The latest scandalette comes at a useful time for the Democrats — they are fighting a battle on tax cuts, which has become wholly tangled. Obama is seeking to extend the Bush tax cuts for yet another year, for those below $250,000 a year; the Republicans are seeking to extend the tax cuts for all, including the super-rich. They have rushed through a bill attaching the cuts to an extra series of cuts for small businesses hiring new employees. The Democrats have now stonewalled this in the Senate, hoping to get their own tax bill through — and to present Romney as a featherbedder of the rich.

Which will be helped immensely if they can paint him as a moustache-twirling, lying rentier.

In any case, the campaign is off and running. And this is how it will be fought — with vast and complex multiple attacks, fuelled by a billion dollars on each side.

Welcome to the dollhouse …