Stimulus spending had always been expected to rise sharply this summer, and the White House has been predicting that 600,000 job total for about a month.

Obama faces souring public opinion over his handling of the economy, which has shed 1.6 million jobs since the stimulus was signed in February. That total has far overshadowed White House announcements estimating the effort has saved 150,000 jobs, a figure that is so murky it can never be verified. Monday’s announcement sought to reposition Obama in the driver’s seat of America’s recovery. It portrayed the president as revving up the engine of the stimulus, but it was something federal agencies were already planning to do anyway.

Obama spoke about “modest progress” in the economy, citing fewer jobs lost last month than expected. He said he hoped to build on that in the months ahead with stimulus programs.

“We’ve done more than ever, faster than ever, more responsibly than ever, to get the gears of the economy moving again,” he said.

But he acknowledged: “I’m not satisfied. We’ve got more work to do.”

And for the first time, the administration conceded the economic forecasts it used to sell the stimulus were overly optimistic.

“At the time, our forecast seemed reasonable,” said Vice President Joe Biden’s top economic adviser, Jared Bernstein, explaining that the White House underestimated the scope of the recession. “Now, looking back, it was clearly too optimistic.”

By this point, according to earlier White House economic models, the nation’s unemployment rate should be on the decline. The forecasts White House advisers used to drum up support for the plan projected today’s unemployment rate would be about 8 percent.

Instead, it sits at 9.4 percent, the highest in more than 25 years. By any measure, spending $44 billion in four months — and with unprecedented transparency — is an uncharacteristic feat in Washington. But the expectations have been even higher, and restoring the economy has proven tougher than the administration expected.

Several economists said Monday the economy was unlikely to see any boost from the stimulus before next year.

“It takes time to organize projects, to get the bids in, the funds out and the work started,” said Nigel Gault, chief U.S. economist at IHS Global Insight.

Obama’s disapproval rating on the economy has risen from 30 percent in February to 42 percent, according to a Gallup poll completed May 31. Sensing weakness on a signature issue of Obama’s presidency, congressional Republicans are renewing their criticisms that the stimulus plan has not shown results, only mounting debt.