(CNN) -- Sen. Barack Obama said Tuesday that the country is facing the "most serious financial crisis in generations" and argued that rival Sen. John McCain would only make it worse.

"I certainly don't fault Sen. McCain for all of the problems we're facing, but I do fault the economic philosophy he subscribes to," Obama said in Golden, Colorado.

Obama said what's happened in the past few days is "nothing less than the final verdict on an economic philosophy that has completely failed."

On Monday, Lehman Brothers -- the 158-year-old Wall Street giant -- filed for bankruptcy protection, and 94-year-old Merrill Lynch sold itself to Bank of America. Both developments sent shock waves through Wall Street.

While Obama was slamming McCain's economic policies, the senator from Arizona campaigned in Tampa, Florida, where he promised to "change the way Washington does business."

"We're going to put an end to the reckless conduct, corruption and unbridled greed that has caused a crisis on Wall Street," McCain said.

Obama on Tuesday again blasted McCain for saying that the "the fundamentals of the American economy are strong."

McCain made the comments Monday but later tried to clarify them.

On Tuesday, he told CNN's "American Morning" that he meant American workers are "the fundamental strength" of the U.S. economy and that the country will rebound with their help.

"What I obviously was saying, and I believe, is the American workers, the most productive and the most innovative -- they are the fundamentals of our economy and the strength of it and the reason why we will rebound," he said. Watch McCain talk about his economic plan »

Obama said Tuesday that McCain's campaign "sent him back out to clean up his remarks ... but we know that Sen. McCain meant what he said the first time."

Obama then went into detail about what he sees as the differences between his plan and McCain's economic policy, listing times when he said he took action and he said McCain did not.

"Make no mistake: My opponent is running for four more years of policies that will throw the economy further out of balance," he said.

The McCain campaign said Obama's comments showed no respect for American workers.

"Aside from inflating his own resume, Barack Obama offered nothing new except for sharp criticisms of the most fundamental elements of the American economy and pessimism about genuine efforts to restore our country's prosperity," spokesman Tucker Bounds said.

"More important than understanding that raising taxes on small businesses during a struggling economy is a bad idea, is respecting the strength of American workers and ingenuity -- sadly Barack Obama demonstrates neither."

As part of his proposal to get out of the economic crisis, Obama said he is proposing a $50 billion Emergency Economic Plan to "jump-start job creation." Obama said the plan would save 1 million jobs by rebuilding infrastructure and repairing schools, among other things. Watch how the economic crisis is playing out in the campaign »

The senator from Illinois said the country also must continue to address the housing crisis and build a "21st-century regulatory framework." Obama vowed to "get serious" about regulatory oversight.

"If you're a financial institution that can borrow from the government, you should be subject to government oversight and supervision," he said.

Obama said the United States needs leadership to get the country out of its financial problems.

"I'll provide it, John McCain won't, and that's the choice for the American people in this election," he said.

But Jeffrey Sachs, a renowned economist and special adviser to the U.N. secretary-general, said neither candidate will be able to stop continued financial woes in the near future.

"I think right now that this is a recession that's going to happen," he said."I don't see anybody being able to stop that giant wave. The question is how we get out if it."

Sachs said he thinks Obama's plan is "closer" to being on target, with his calls for regulation. McCain also has started talking about increased regulation, but Sachs said McCain has "reinvented himself in the last 24 hours" with such talk.

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