WASHINGTON -- Even if Congress heeds President Barack Obama's demands to "pass this bill right away" and enacts his jobs and tax plan in its entirety, the unemployment rate probably still would hover in nosebleed territory for at least three more years.

Why? Because the 1.9 million new jobs the White House said the bill would produce in 2012 falls short of what's needed to put the economy back on track to return to pre-recession jobless levels of under 6 percent, from today's rate of 9.1 percent.

That's how deep the jobs hole is. The persistent weakness of the U.S. economy has left 14 million people unemployed and more than 25 million unable to find full-time work.

Economists of all stripes pretty much agree that it will be a long, hard road no matter what Congress does. Right now, the Republicans who run the House and the Democrats who lead the Senate aren't finding much common ground.

Obama has estimated that his American Jobs Act would lower unemployment by just a single percentage point by next year, to just over 8 percent, heading into the 2012 presidential election.

Burned before by making overly optimistic job-creation predictions, the White House turned to prominent outside economists to crunch the numbers.

The projection of 1.9 million new jobs, a 1 percentage point drop in the unemployment rate and a 2 percentage point increase in the gross domestic product under Obama's plan came from Mark Zandi, chief economist of Moody's Analytics.

Zandi also said that his forecast is based on an assumption that "the president's entire package is passed by the end of the year," a slim prospect given the current divided leadership in Congress, and that there are no other budgetary policy changes.

"I assumed that it would be paid for," Zandi said. "I didn't know when I did that simulation how the president proposed to pay for it."

Since then, Obama has said he would pay for his $447 billion package with permanent income tax increases of about $150 billion a year, mostly on wealthy individuals and corporations, in addition to spending cuts.

That has drawn criticism from Republicans, who say any tax increases could further stall the fragile recovery.

Zandi, who has advised Republican and Democratic lawmakers, said he is sticking with his forecast, mainly because the stimulus in the plan, including a temporary reduction in Social Security taxes for employees and employers and infrastructure spending, would come in 2012 and be paid for later.

But there is one feature Obama doesn't emphasize.

Zandi said his job-creation figure applies only to 2012.

"Beginning in 2013, and certainly into 2014, the plan is a drag on the economy because the stimulus starts fading away," he said. "So by 2015, the economy is in the same place as now, as if there were no jobs package."

Also, Zandi said, his forecast does not leave any room for a new recession. If that happens, all bets are off.

"So it's very important to get as many people working as fast as possible," he said. "If we go back into recession, it is going to be very difficult to get out."