President Obama declared Thursday that he and Republican opponent Mitt Romney offer radically different, irreconcilable visions for how to lead the nation back to prosperity, saying it is up to voters to “break that stalemate.”

The president’s 54-minute speech here, which at times had the ring of a State of the Union address, represented an effort to regain his footing and reframe his argument for reelection after two weeks of dismal economic and political news.

Obama offered the most vigorous defense of his presidency to date, one that included a litany of the actions — including investment in schools, energy and infrastructure — that he said have strengthened the middle class and fostered economic growth. After what his aides billed as a major address, the Obama campaign flooded supporters with statements from about two dozen surrogates hailing the speech for its insights, part of an effort to curb Democratic dissent and help the president set the agenda for the coming days.

But Romney did not cede the stage in this bellwether state that both campaigns consider crucial.

The presumed Republican nominee scheduled his remarks at a Cincinnati factory so that they would come shortly before Obama’s, to serve as a prebuttal. And at the site of the president’s speech at Cuyahoga Community College, a Romney campaign bus circled the event, honking its horn, while a few dozen protesters milled on street corners nearby.

Obama’s speech underscored how much circumstances have changed for him since he won the presidency in 2008 on a promise of hope and change. The national mood this time is one of disillusionment, both with the slow pace of the economic recovery and with dysfunction in Washington.

“The only thing that can break that stalemate is you,” Obama told the nation. “What’s lacking is not the capacity to meet our challenges. What is lacking is our politics. And that’s something entirely within your power to solve.”

Where Obama ran four years ago as an inspirational figure who could rise above partisanship, his argument on Thursday suggested that there is no common ground between his approach to governing and Romney’s.

“This election presents a choice between two fundamentally different visions of how to create strong, sustained growth, how to pay down our long-term debt, and most of all how to generate good, middle-class jobs so people can have confidence that if they work hard, they can get ahead,” the president said.

“This isn’t some abstract debate,” he continued. “This is not another trivial Washington argument.”

As he has in the past, Obama blamed the policies of George W. Bush, his predecessor, for digging and deepening the hole in which the economy remains, and Republican obstructionism for the lack of progress in digging out of it.

Romney, he said, would take the country back to Bush’s approach, by cutting taxes for the wealthy, strangling investment in the future and lifting regulations. The result, he said, would be cuts in popular programs, such as college loans, medical research and early childhood education; a repeal of the new health-care law; and the transformation of Medicare into a voucher program.

“This is their economic plan. It has been placed before Congress,” Obama said, linking Romney to that unpopular institution. “If they win the election, their agenda will be simple and straightforward. They have spelled it out.”

His proposal, he added, is to increase investments in education and training, to encourage alternatives to oil, and to put more money toward research and infrastructure.

Romney was dismissive of Obama’s address even before it was delivered, calling it a substitute for results.

“You may have heard that President Obama is on the other side of the state and he’s going to be delivering a speech on the economy. He’s doing that because he hasn’t delivered a recovery for the economy,” the Republican said. “And he’s going to be a person of eloquence as he describes his plans for making the economy better, but don’t forget he’s been president for 31 / 2 years, and talk is cheap. Actions speak very loud.”

Romney added that Obama’s policies have “made it harder for entrepreneurs to start a business” and have “made it less likely for businesses like this to hire more people.”

The dueling speeches came at a moment of high anxiety for Obama’s Democratic allies, who have lost some confidence in his ability to vanquish what many of them had once regarded as a weak Republican opponent. Some have urged an overhaul of the president’s message, one less focused on Bush’s record and more attuned to the economic pain that Americans continue to feel.

In a memorandum earlier this week, political consultant James Carville and pollster Stan Greenberg warned that Obama could face “an impossible headwind in November if we do not move to a new narrative.”

Obama’s strategists, however, have said that as president, he has no choice but to stand on his record, even as he argues that he offers a better route for the future.

The speech did include evidence that Obama’s team is trying to elevate and sharpen his message. The president did not repeat the attacks that his campaign has made on Romney’s record, both as a corporate turnaround artist and as a governor of Massachusetts. Instead, he aimed to provide a contrast to their visions.

And although many of his lines brought cheers from the crowd of an estimated 1,500, Obama said, “I want to speak to everybody who is watching who may not be a supporter, may be undecided or thinking about voting the other way. . . . If you want to give the policies of the last decade another try, then you should vote for Mr. Romney. . . . You should vote for his allies in Congress. You should take them for their word.

Obama made a nod to the political difficulties he is facing. Some of them, he acknowledged, have been of his own making.

“Over the next five months, this election will take many twists and many turns. Polls will go up and polls will go down,” he said. “There will be no shortage of gaffes and controversies that keep both campaigns busy and give the press something to write about. You may have heard I recently made my own unique contribution to that process.”

That was a reference to Obama’s statement at a news conference last Friday that “ the private sector is doing fine.”

It was part of a larger point that Obama made that the public sector is shrinking, even while private companies are hiring.

But his words were tone-deaf enough to spawn a wave of Republican advertisements, including one released Thursday by the Romney campaign that juxtaposes the president’s words with images of unemployed workers standing in line and grim economic statistics.

Staff writer Philip Rucker contributed to this report.