He said the recession has left the nation so weak that only the federal government can "jolt our economy back to life." And he declared that failure to act swiftly and boldly "could turn a crisis into a catastrophe."
"The party now is over," he said.
Speedy passage of legislation to pump federal money into the crippled economy, once seemingly assured with bipartisan support, has become a much heavier lift and a major test of Obama's young presidency. With more than 11 million Americans now out of work, Obama defended his program against Republican criticism that it is too big, loaded with pork-barrel spending and won't create jobs.
"The plan is not perfect," the president said. "No plan is. I can't tell you for sure that everything in this plan will work exactly as we hope, but I can tell you with complete confidence that a failure to act will only deepen this crisis as well as the pain felt by millions of Americans."