GOLDEN, Colo. — Republican presidential candidate John McCain on Tuesday blamed Wall Street's financial turmoil on unchecked corporate greed. His Democratic opponent, Barack Obama, dismissed McCain's call for a high-level commission to study the economic crisis as "passing the buck."

The presidential campaigns argued over who would be best able to deal with the kinds of financial meltdowns that roiled the markets Monday and to prevent a similar crisis in the future. McCain proposed a review on the order of the one led by the Sept. 11 commission, the bipartisan panel that studied the events leading to the 2001 terrorist attacks.

"We need a 9/11 commission," McCain said Tuesday on NBC's "Today" show. "We need a commission to figure out what went wrong and how to fix it and I know we can do that and I'll do it."

Obama, campaigning in Golden, Colo., accused McCain of failing to offer concrete plans for dealing with economic issues.

"Sen. McCain offered up the oldest Washington stunt in the book. You pass the buck to a commission to study the problem," Obama said. "This isn't 9/11. We know how we got into this mess. What we need now is leadership that gets us out. I'll provide it. John McCain won't. And that's the choice for Americans in this election."

Obama continued to criticize McCain's remark Monday that "the fundamentals of our economy are strong." In a television ad released Tuesday, Obama's campaign asks: "How can John McCain fix our economy if he doesn't understand it's broken?"

On Monday, a few hours after the remark about strong economic fundamentals, McCain backtracked and declared the economy to be in crisis. He also said that American workers and products — the "fundamentals" he claimed he was referring to earlier — were indeed sound but faced danger from greed and corruption.

"Those fundamentals are threatened, they are threatened and at risk, because some on Wall Street have treated Wall Street like a casino," McCain said Monday at a town-hall meeting in Orlando, Fla.

In spite of a speedy rhetorical reversal, the Arizona senator was widely criticized for offering a seemingly upbeat outlook while the stock market was on its way to a loss of 500-plus points and new troubles arose for investment banks. Appearing on ABC's "Good Morning America" on Tuesday, McCain said he had warned two years ago of a deteriorating and unacceptable situation and blamed "the old-boy network and the corruption in Washington."

McCain offered no specific remedies during his appearances on the three network morning shows, though he said he agreed with Treasury Secretary Henry Paulson that the government should not bail out American International Group Inc., the world's largest insurer. AIG stock fell 61 percent on Monday and credit-rating agencies dropped its ratings amid worries that the deteriorating housing market was further undermining its finances.

Saying that the American taxpayer should not be "on the hook" for AIG, McCain said: "We cannot have the taxpayers bail out AIG or anybody else. This is something that we're going to have to work through."

Later, a McCain economics and policy adviser, Douglas Holtz-Eakin, said any plan should include regulation of all sorts of financial institutions, consumer protections, improved corporate governance and "systems stability" programs.

"There's no magic solution, and I don't think it's at this moment imperative to write down exactly what the plan has to be," said Holtz-Eakin. "But there should be an understanding that when you walk out of the Congress with a piece of legislation in the next administration, those boxes are checked and those things are effectively accomplished."

Democratic vice presidential candidate Joe Biden countered that the Republican campaign's message was at odds with itself with McCain saying the economy's fundamentals were sound but that urgent repairs were needed.

"It seems like John's had an epiphany. Nine o'clock yesterday morning, John thought the economy was going great guns and the Bush administration was doing well, and today he thinks it's in crisis," Biden said on CBS' "The Early Show."

Biden said the Democratic presidential campaign's solutions for the economic crisis include giving middle-class taxpayers a substantial tax break, putting an end to Bush administration tax cuts that favor the wealthy, investing in infrastructure, and changing bankruptcy laws to help people facing foreclosure.

"My lord, take a look at what — who got us in this hole, whose policies," Biden said. "This has been a Republican philosophy of letting Wall Street do what they want and the middle class be damned. It's about time we change it. If I sound like I'm angry, I am fighting mad for middle-class people who have been the scapegoat of this economy because of the policies of the McCains and the Bushes."