WASHINGTON — Politically and economically, the next three months are critical for Barack Obama's presidency. The pace of the economic recovery heading into the fall — electric smooth or diesel rough — will determine whether Obama can prod Congress on the key features of his agenda with momentum or from a defensive crouch.

Steady economic improvement that is perceptible to the American public would boost his political standing and give him the thrust to get Congress to complete action on his ambitious plans to overhaul health care, attack climate change and put the financial sector under greater government oversight.

But a stumbling recovery would erode Obama's currently high approval ratings, a source of much of his political power. At the same time, continued high unemployment might force Obama to ask Congress for another boost in spending to stimulate the economy — a political challenge that could delay if not undermine his other goals. So far there is little cause for cheer.

Since Obama signed the $787 billion economic stimulus bill in February, the economy has shed more than 2 million jobs.

Economists and heavyweight Obama backers such as Warren Buffett already are calling for another stimulus, saying the recession proved to be deeper and more devastating than originally believed.

"The economy took away everything they put on the table," said Lawrence Mishel, president of the Economic Policy Institute, a labor-leaning economic think tank.

"We strongly believe we need another stimulus, and we need it now," added Thea Lee, the policy director for the AFL-CIO.

The need for a new stimulus has been a matter of internal debate within the Obama administration, according to people familiar with internal discussions. But White House officials have made no public commitments.

Vice President Joe Biden said the administration "misread how bad the economy was" but stands by its stimulus package and believes the plan will create more jobs as the pace of its spending picks up.

The conundrum for Obama is that his health care and climate plans ultimately rely on a strong economy. A weak recovery that falls short of the administration's forecast of 3.2 percent growth in gross domestic product in 2010 would result in lower than expected revenue and greater potential deficits over time.

Trying to further prime the recovery, however, would require additional short-term deficit spending and there's declining appetite for that in Congress as well.

Analysts and the administration officials say the full effect of the $787 billion is only beginning to be felt. But that initial beneficial shock to the system will dissipate and if the economy is still sputtering next year, it could become a political danger for Democrats.

"The economy is obviously being supported by significant stimulus," said economist Mark Zandi of Moody's Economy.com, who has advised Washington policy makers. "But that's going to begin to fade by certainly this time next year, right in time for the next election."

Many of those favoring a stimulus say it should be smaller than the current one. Estimates range from less than $200 billion to up to $500 billion. Advocates say it should contain unemployment assistance and aid to states. While some reject tax cuts as an element, others say it could include a payroll tax holiday.

Labor intends to make a louder case for a new stimulus. AFL-CIO President John Sweeney issued a statement calling on the administration to "remain focused on stimulus efforts" and issued an international call for governments to increase stimulus spending by 1 percent of GDP.