DETROIT, Michigan, (AFP) - - White House hopeful Barack Obama said his Republican rival John McCain was guilty of "Katrina-like" bungling over the US financial crisis, as a new post-debate poll gave the Democrat a decisive lead.

Both the contenders for the November 4 election said Sunday a drastically reshaped deal to bail out Wall Street, set to go before a vote in Congress after a weekend breakthrough by senior lawmakers, was a bitter but necessary pill.

Obama said it was an "outrage" that taxpayers had to rescue financiers from their own folly but, like McCain, argued the world's biggest economy was at risk of disaster without government action.

The Democrat, addressing a mammoth crowd of 35,000 at a boisterous rally here, said McCain "doesn't understand that the storm hitting Wall Street hit Main Street long ago."

"That's why his first response to the greatest financial meltdown in generations was a Katrina-like response. Sort of stood there, said the fundamentals of the economy are 'strong,'" Obama said.

"That's why he's been shifting positions these last two weeks, looking for photo-ops, trying to figure out what to say and what to do," he told the rally, joined by his running mate Joseph Biden and their wives.

Obama was evoking the widely slammed response of President George W. Bush's administration to Hurricane Katrina in 2005, and making a pointed reminder of McCain's ties to a deeply unpopular Republican leader.

The Democrat was also mocking his rival senator's role in the delicate congressional negotiations over the rescue package, after McCain said last week he was suspending his campaign to rush back to Washington.

McCain insisted he played a key role by reaching out to Republicans in the House of Representatives who remain angry over the government's biggest financial intervention since the Great Depression.

"I came back because I wasn't going to phone it in," he told ABC News, although he had spent Saturday telephoning leaders in Congress from his home in the Washington suburbs rather than going himself to Capitol Hill.

"I saw that the House of Representatives was not engaged, that the Republicans in the House of Representatives were not engaged in the negotiations.

"They're the most fiscally conservative people. And so I came back."

Both McCain and Obama said the deal now finalized and ready for voting took into account their demands including strong congressional oversight and a ban on "golden parachute" payoffs for busted Wall Street bosses.

The Democrat noted that the deal also encompassed new relief for hard-pressed homeowners.

Two days after the presidential rivals clashed at their first debate, McCain said: "This is something that all of us will swallow hard and go forward with. The option of doing nothing is simply not an acceptable option."

Gallup's latest tracking poll , which took into account McCain's dramatic gambit in suspending his campaign and voters' initial reactions to Friday's debate, had Obama with a yawning lead of 50 percent to 42.

Neither McCain, 72, nor Obama, 47, landed a decisive blow in the debate at the University of Mississippi. But telephone polls immediately after scored a win for the Democrat, who was already pulling well ahead in surveys last week.

Introducing Obama in Detroit, Senator Biden said McCain had been absent from economic discussions for years, and that Obama "owned the turf" on foreign policy at the debate.

Biden recapped McCain's vow to follow Al-Qaeda leader Osama bin Laden to the "gates of hell" but his opposition to Obama's call for US strikes on extremist leaders in Pakistan, if the Islamabad government is unable or unwilling to act.

"President Barack Obama will follow him (bin Laden) to where he lives and then send him to hell!" the vice presidential nominee exclaimed.

McCain's own running mate, Alaska Governor Sarah Palin, said Saturday on the question of launching raids in Pakistan: "If that's what we have to do to stop the terrorists from coming any further in, absolutely, we should."

McCain denied that Palin had endorsed Obama's position and contradicted his own.

He said on ABC "this is a free country, but I don't think most Americans think that that's a definitive policy statement made by Governor Palin."