Washington ? So much for bipartisanship.

Day after day of Republican sniping at President Barack Obama and the massive economic recovery bill he wants Congress to pass quickly appeared to get the best of the leader who pledged to govern across party lines and mend old, bitter partisan divisions. In an hourlong prime-time news conference Monday, Obama shot back repeatedly with biting, sarcastic asides about GOP lawmakers who say the bill is too big, loaded with pork-barrel spending and won’t create jobs.

“It’s a little hard for me to take criticism from folks about this recovery package after they’ve presided over a doubling of the national debt,” the president said. “I’m not sure they have a lot of credibility when it comes to fiscal responsibility.”

He added: “You get a feeling that maybe we’re playing politics instead of actually trying to solve problems for the American people.”

With 11 million Americans out of work, Obama turned the first formal news conference of his three-week-old presidency into a determined defense of his emergency plan.

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 for Obama’s administration.

“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.”

Obama said the country could well be in better shape by next year, as measured by increased hiring, lending, home values and other factors. “If we get things right, then, starting next year, we can start seeing significant improvement,” Obama said.

On the day that an $838 billion version of the stimulus legislation cleared a crucial test vote in the Senate, Obama warned darkly of what he said would be the consequences of inaction, addressing the nation from the East Room of the White House.

“This is not your ordinary, run-of-the-mill recession,” he said. Obama said the United States could tumble into the kind of economic pain that Japan endured in the 1990s — the “lost decade” when that nation showed no economic growth.

He hit repeatedly at the themes he has emphasized in recent weeks, including at a town hall meeting earlier in the day in recession-battered Elkhart, Ind., where layoffs in its mainstay recreational vehicle industry has sent unemployment above 15 percent.

It’s a time-honored presidential strategy: talking to voters to get lawmakers to listen.

Originally, aides had insisted that Obama’s time would be better spent remaining in Washington to shepherd the stimulus bill. But as difficulties with the legislation grew, aides scheduled the Monday trip and news conference, as well as other travel to hard-luck communities. Obama is traveling today to Fort Myers, Fla., and on Thursday to Peoria, Ill.

He seemed cool and unruffled as he fielded 13 questions before a nationwide audience of millions. He ducked several questions, for example refusing to say if his administration would alter the Bush administration’s policy of refusing to allow photographs of flag-draped coffins of America’s war dead.

He also refused to say how long U.S. troops would be in Afghanistan after his planned troop buildup there. And he refused to reveal details of new rules governing the bailout of financial firms, set to be announced today by his Treasury secretary.

Obama defended his efforts at bipartisanship, despite the precious few concrete results so far. Not a single House Republican voted for the legislation last month, and only three GOP senators supported it on Monday. Obama noted he had put Republican tax cuts into the plan and kept them there, negotiated with GOP lawmakers individually and as a group, and even put three Republicans in his Cabinet.

“All those were not designed simply to get some short-term votes. They were designed to try to build up some trust over time,” he said. “And I think that, as I continue to make these overtures, over time, hopefully that will be reciprocated.”

But the talk of mending the partisan divide only went so far. Obama took Republicans for trying “to play the usual political games.”

The Gallup Organization released a poll Monday showing Obama’s approval rating holding steady at 67 percent, with Congress much less popular. Republicans in Congress drew only 31 percent approval, and Democrats had 48 percent. The poll also showed that 80 percent think it’s either important or critically important that a stimulus plan be approved.

The White House is calculating that such numbers, along with Obama’s daily drumbeat, will help him win the day as the stimulus legislation moves forward.

The Senate was expected to pass it today. Then it must be reconciled with a $820 billion House bill in negotiations expected to be difficult.

While Obama focused on the economy in the opening minutes of the news conference, he also faced questions on foreign policy.

He said his administration would look for opportunities “in the coming months” for direct talks with Iran, a nation accused by the United States of supporting terrorism and pursuing nuclear weapons.

Ticking off a myriad of concerns about Iran’s support for terrorist groups, its nuclear weapons program and its anti-Israel stance, Obama said Iran must send conciliatory signals as the U.S. is. But he also acknowledged distrust on both sides of the relationship. “There’s the possibility at least for a relationship of mutual respect and progress,” he said.

He also said that signing condolence letters to the families of fallen American soldiers made his new job real like no other task. “It reminds you of the responsibilities that you carry in this office and — and the consequences of the decisions that you make,” Obama said.

He also:

• Called Alex Rodriguez’s admission that he used steroids “depressing news” that tarnishes an entire era of major league baseball. The All-Star third baseman with the New York Yankees told ESPN on Monday he used banned substances while playing with the Texas Rangers from 2001-03.

• Suggested it was unlikely his administration would seek to prosecute anyone involved in harsh interrogations of terrorism suspects.

• Said Pakistan has not provided “the kind of concerted effort to root out those safe havens” used by al-Qaida in its lawless, mountainous border region near Afghanistan.