Top Senate Democrats have put the onus on House Republicans, saying they are unwilling to accept higher tax revenues as part of a balanced approach to replacing the cuts.

Another factor is at work in the House - the increasing influence of deficit hawks who believe the military should shoulder more of the deficit reduction burden. Traditionally, Republicans, including Ryan, last year’s Republican vice presidential nominee, have tried to protect military programs.

“The momentum has shifted to those in the caucus who believe that the only savings we’re ever going to get are going to be the sequester savings,” said Bell.

Those fiscal conservatives believe Obama will not negotiate with them or agree to any significant cuts in social programs.

He added that it was possible that in the absence of a deal, Congress could provide some legislative language that gives domestic agencies and others some flexibility in making their cuts, rather than accept them in their current, across-the-board form.

Some Democrats are voicing concern the cuts could do serious economic damage.

“I think there should be a sense of urgency, because ... we’re looking at an economy struggling to recover and the number of people who we want to have jobs who are still unemployed,” said Democratic Senator Jean Shaheen of New Hampshire.

“A failure to take action on what we know is going to have a significant impact on that is simply unacceptable,” said Shaheen, a member of the Senate Armed Services and Appropriations committees.

Northrop Grumman, which builds electronics and unmanned surveillance planes, warned that profits this year would fall sharply due to the increasing pressure on the defense budget.