Obama acknowledged in his weekly radio and Internet address that people are getting nervous about continuing high joblessness - the unemployment rate hit 9.5 percent in June - but said that reversing payroll losses takes time. He asked Americans to be as patient as possible.

Republicans have labeled the $787 billion stimulus a failure. Both Obama and Vice President Biden have argued that the bulk of the money from the stimulus program is still being disbursed and that it already had saved many jobs.

Obama criticized Republicans for opposing the stimulus but offering few alternatives to the worst recession since the Great Depression. And he rejected talk of a second stimulus, an idea that has been discussed by Democrats and even famed investor Warren Buffett.

"We must let it work the way it's supposed to, with the understanding that in any recession, unemployment tends to recover more slowly than other measures of economic activity," Obama said in his message, which had been recorded earlier.

The stimulus included $288 billion in tax cuts, dramatic increases in Medicaid spending, about $48 billion in highway and bridge construction, and billions more to boost energy efficiency, shore up state budgets, and improve schools.

The plan "was not designed to work in four months," Obama said. "It was designed to work over two years."

Since Obama signed the stimulus into law, the economy has lost more than two million jobs and the unemployment rate has climbed higher than the White House predicted it would have ever reached without the stimulus.

Some companies say stimulus money helped avoid layoffs. Independent government auditors found that stimulus aid to states helped keep teachers off unemployment lines. But overall job numbers continue to suffer.

Republicans have seized on this opportunity to criticize the president.

With the Obama administration now pushing for a costly overhaul of the nation's health-care system, Republicans are casting Democrats as liberals on a shopping spree. In the GOP's weekly address yesterday, Virginia Rep. Eric Cantor, the House Republican whip, accused the Democratic-controlled Congress of reckless spending and careless borrowing.

"For the stimulus alone, Washington borrowed nearly $10,000 from every American household," Cantor said. "Let me ask you: Do you feel $10,000 richer today?"

In his speech, Obama twice referred to "cleaning up the wreckage" of a recession that began on President George W. Bush's watch. But with Obama's poll numbers slipping on economic issues, Republicans want to lay the economy at the president's feet.

"This is now President Obama's economy," Cantor said.