In his most forthright reaction yet to the government's US$700 billion (S$1 trillion) proposal to buy up distressed mortgage assets, the White House contender also accused Republican rival John McCain of helping to run the economy aground.

Addressing an enormous crowd of 20,000 people at an open-air rally here, Mr Obama said President George W. Bush's administration has so far 'only offered a concept with a staggering price tag, not a plan.'

Opposing a 'blank check when American taxpayers are on the hook for this much money,' the Illinois senator said 'this initial outlay of up to (US)$700 billion dollars is sobering' even if the Treasury recoups its money over time.

'And in return for their support, the American people must be assured that the deal reflects the basic principles of transparency, fairness, and reform.'

In line with Treasury Secretary Henry Paulson, Mr Obama said that US trading partners must help shoulder the burden of fixing the 'global crisis' sweeping through the interconnected financial system.

But unlike Mr Paulson and other Republicans, who called for a simple rescue deal, Mr Obama said the plan working through Congress must protect hard-pressed voters on 'Main Street' and not just corporate managers and shareholders.

'The era of greed and irresponsibility on Wall Street and in Washington has led us to a perilous moment. They said they wanted to let the market run free but instead they let it run wild,' he said.

'We have to come together, as Democrats and Republicans, to pass a stimulus plan that will put money in the pockets of working families, save jobs, and prevent painful budget cuts and tax hikes in our states.'

The crisis has helped to restore Mr Obama's lead in the polls, with the latest Gallup tracking survey on Sunday putting the Democrat at 49 per cent to 45 for Mr McCain. However, he had a six-point lead over the Republican on Saturday.

Mr Obama said the crisis was an indictment of Mr Bush and Mr McCain's zeal for deregulation, and queried how his Republican opponent in the November 4 election could argue 'with a straight face' to be a maverick reformer.

He reprised his attack from Saturday that Mr McCain now wanted to inject Wall Street-style competition into healthcare insurance and would jeopardise Social Security retirement benefits through enacting private investment accounts.

'We're now seeing the disastrous consequences of this philosophy all around us - on Wall Street as well as Main Street,' the Democrat said.

'And yet Senator McCain, who candidly admitted not long ago that he doesn't know as much about economics as he should, wants to keep going down the same, disastrous path,' he said.

'And I am running for president of the United States because the dreams of the American people must not be endangered any more. At this defining moment, we have the chance to finally stand up and say: enough is enough!'

In a 'statement of principles', Mr Obama outlined his own priorities in response to the government plan, which his economic aide Austan Goolsbee told CNN contained less information than 'a box of Froot Loops' breakfast cereal.

Mr Obama said his principles included no open-ended offer to Wall Street without greater transparency and oversight, help for homeowners to stay in their homes, and 'a regulatory structure for the 21st century.'

But McCain spokesman Tucker Bounds said Mr Obama was offering no concrete solutions of his own to fix the financial crisis and was therefore 'just not ready to lead.' -- AFP