Mitt Romney, one of the contenders for the Republican presidential nomination, dismissed the president’s address. “I thought, ‘In what way is he like Teddy Roosevelt?’ ” Mr. Romney said. “Teddy Roosevelt founded the Bull Moose Party. One of those words applies when the president talks about how he’s helped the economy.”

The trip was Mr. Obama’s third out of Washington in as many weeks to press for passage of the payroll tax break, which would reduce the how much employees pay for Social Security to 3.1 percent from the already reduced level of 4.2 percent. Under the Democratic proposal, which Republicans have blocked, the cut that would go to most working Americans would be offset in the budget by a 1. 9 percent surtax on those with modified adjusted gross incomes of more than $1 million. If Congress takes no action, the tax will revert back to 6.2 percent next month.

In Washington, the two parties remained at an impasse in their efforts to write legislation to extend the tax cut, with Senate Republicans rejecting the latest Democratic proposal and House Republicans still writing their own plan.

Though the earlier speeches on the payroll tax took place in swing states, the fact that the president brought the message to one of the most reliably Republican states in the country shows that he and his party are increasingly confident that they have found a message that resonates with voters.

This speech, however, was cast in broad historical terms, with Mr. Obama declaring that that after a century of struggle to build it, the middle class has been steadily eroded, even before the current economic turmoil, by Republican policies intended to reduce the size and scope of government — ranging from tax cuts for the wealthy to deregulation of Wall Street.

“Fewer and fewer of the folks who contributed to the success of our economy actually benefited from that success,” he said. “Those at the very top grew wealthier from their incomes and investments than ever before. But everyone else struggled with costs that were growing and paychecks that weren’t — and too many families found themselves racking up more and more debt.”

Mr. Obama sought to pre-empt a Republican response that he was engaging in class warfare. “This isn’t about class warfare,” he said. “This is about the nation’s welfare.”