With chaos rocking financial markets, John McCain assailed "greed and corruption" on Wall Street and promised to clean it up, while Barack Obama blamed White House policies and said his opponent would only deliver more of the same.

The US presidential candidates struggled on Monday to seize control of the issue voters say is most important – the economy – with Republicans and Democrats alike saying the man who succeeds may well win the election. 

However, in a dizzying day of speeches and statements, neither White House hopefuls offered any fresh ideas for turning things around. Instead each relied on the same vague, though vastly different, pitches he has sounded over the past few months for fixing what ails the country.

And they didn't emphasize that they are part of the US Congress that has done little to head off the crisis. McCain is a four-term Arizona senator, Obama a first-termer from Illinois.

Bemoaning "the most serious financial crisis since the Great Depression," Democrat Obama faulted Republican McCain's domestic policy agenda as the same as US President Bush's – "one that says we should just stick our heads in the sand and ignore economic problems until they spiral into crises."

McCain declared in a new TV ad, "Our economy is in crisis. Only proven reformers John McCain and Sarah Palin can fix it" – though he also told voters in Jacksonville, Fla., "The fundamentals of our economy are strong."

While presidents – and candidates of the party occupying the White House – often take credit for good economies and try to avoid blame for bad ones, financial crises nearly always have multiple causes.

Home loans became more affordable a few years ago when the Federal Reserve kept interest rates low. Politicians of all stripes encouraged home ownership. But lightly regulated financial outfits began slicing and dicing the resulting mortgages into securities and selling them to investors.

Eventually, it all began collapsing, prices dropped, people started losing their homes and Wall Street went into a spin.

This is the backdrop with some seven weeks left in the campaign, and both Obama and McCain are trying to find a message that resonates with anxious voters who are fretting about their retirement nest eggs, home mortgages and job security.

As different as their policies are, they were united in their message to voters: It's not your fault.

Courting working class voters who gave him grief in the Democratic primary, Obama sounded an I-feel-your-pain note.

Obama lamented Republican policies over eight years that he said "encouraged outsized bonuses to CEOs while ignoring middle-class Americans" and said: "Instead of prosperity trickling down, the pain has trickled up – from the struggles of hardworking Americans on Main Street to the largest firms of Wall Street."

McCain's words were sympathetic as well.

"America is in a crisis today," he said – then added: "The economic crisis is not the fault of the American people. Our workers are the most innovative, the hardest working, the best skilled, the most productive, the most competitive in the world ... But they are being threatened today ... because of greed and corruption that some engaged in on Wall Street and we have got to fix it."

Some in the markets, he said, "have treated Wall Street like a casino."