WASHINGTON » President Barack Obama and congressional Democratic leaders sought to reset their agenda as they lost their 60th vote in the Senate on Thursday, trying to push ahead with measures to spur job creation even as they grasped for ideas to keep alive their health care legislation.

On the day Scott Brown of Massachusetts was sworn in as the 41st Republican senator, Democrats offered only the bare outlines of their approach to jobs legislation and met at the White House to hash out a strategy for their agenda.

The core of the proposal will probably be a payroll tax break for employers who hire workers who have been without jobs for at least 60 days. Democrats are trying to enlist Republican support for that approach, which was proposed most recently by Sens. Charles E. Schumer, D-N.Y., and Orrin G. Hatch, R-Utah.

Democrats were hoping that the support of at least a few Republicans could build momentum behind a bill now that they no longer have the 60 votes that allowed them to break Republican filibusters solely from within the Democratic ranks.

Negotiators on the Senate Finance Committee were said to be nearing an agreement on the core components of a jobs package, including the payroll tax relief and an extension of a portfolio of existing tax breaks, including incentives for research and development.

But a deal remained elusive on Thursday evening as senators tried to work out details including how to pay for the jobs proposal. Democrats were also pushing to include an extension of unemployment benefits and of health care coverage for those out of work. Discussions were also under way about potentially attaching other initiatives, including a provision to prevent a steep cut in Medicare payment rates for doctors and a reauthorization of money for highway repairs.

The majority leader, Harry Reid of Nevada, said that the Senate would move forward with a jobs package on Monday with or without bipartisan agreement but that he was hoping for cooperation. “;That really would be good for the country and good for us,”; he said. But he warned that he was prepared to push forward with his own proposal if an agreement could not be reached.

Showing the difficulty of finding common ground, a senior aide to the Senate Republican leader, Mitch McConnell of Kentucky, issued a quick statement questioning the Democrats' lack of job specifics. “;They don't know what's in the bill or how many jobs they expect it to 'save or create' or when anyone beyond the Beltway will see it or how much it will cost,”; the aide, Don Stewart, said.

At the White House, Obama and the four Democratic congressional leaders met to set priorities for the legislative agenda given the new circumstances on Capitol Hill.

Without a clear path forward on health care, the president was discussing a job-creation bill and other economic measures, along with financial regulatory reform and energy initiatives.

“;I have no doubt that there will be plenty in any package that can and should garner support, from the Democratic side as well as the Republican side,”; said Robert Gibbs, the White House press secretary.

With the new makeup of the Senate in place, Obama issued a fresh call for Democrats and Republicans to quit questioning one another's motives and to make an effort to move beyond the cynicism and political gamesmanship that has weighed down the politics of Washington.

“;Civility is not a sign of weakness,”; Obama told a bipartisan audience at the National Prayer Breakfast on Thursday morning. The efforts at trying to smooth relations between the two parties had clear limits, though, which were underscored by the president's appearances on Thursday evening at two Democratic fundraising events in Washington.

And Rep. John A. Boehner, R-Ohio, the Republican leader, said Thursday that Republicans had not decided whether they would participate in a bipartisan commission the president plans to establish to examine ways to lower the deficit.

“;We've not seen any details of this so-called commission,”; Boehner said. “;If it's truly going to be a bipartisan effort, then the creation of the commission ought to be done in a bipartisan effort.”;

With the exception of Vice President Joe Biden swearing in Brown, the White House did not publicly acknowledge the political shift in the Senate. But at a Democratic fundraising event on Thursday evening, Obama conceded that the path ahead would be difficult.

“;I know some of you might be discouraged because changing the ways of Washington is hard—it's harder than a lot of you thought it might be,”; Obama told his supporters. “;Sometimes it might make you feel like it's not possible and you want to give up. Don't give up. I don't want you to feel discouraged.”;

After his swearing-in, Brown, who has become something of a national political celebrity from the attention that focused on the Massachusetts special election, said he was ready to get to work.

“;I can't promise I will be right in very vote I make,”; he said. “;I am sure I will make mistakes from time to time. However, I have always tried to learn and grow and will do the very best job that I can on an everyday basis.”;