The Senate Democrats return to work this week feeling battered, weak and almost desperate to quickly power through what has become a politically damaging health care debate.

[IMGCAP(1)]And if things weren’t bad enough, Democrats are hoping they won’t wake up Wednesday with one fewer Democrat in their ranks, a situation that could make it impossible to pass a final health care bill this year.

Over the weekend, the party — and the president — pulled out all the stops to ensure that Massachusetts Attorney General Martha Coakley (D) pulls out a win in today’s special election against upstart GOP candidate Scott Brown. A Brown win would prove all the more humiliating to Democrats considering he would replace the liberal lion, the late Sen. Edward Kennedy (D-Mass.), who said in his last days that health care reform was “the cause of my life.—

A Coakley loss would end the Democrats’ nearly six months with a filibuster-proof 60-vote majority and would only add to weeks of bad news for Senate Democrats, including Majority Leader Harry Reid’s (Nev.) impolitic remarks about President Barack Obama’s race and the announcements that Sens. Chris Dodd (Conn.) and Byron Dorgan (N.D.) are retiring.

Seeing their opponents struggle, Republicans are unlikely to let up on the partisan pressure they’ve applied for the past year.

“Republicans haven’t had this much confidence in a very long time,— one senior Senate GOP aide said. “Everywhere you turn there is more evidence that the American people are identifying with what Republicans have been saying and doing, and we’re walking back into Congress next to a group of Democrats who must know by now that they’ve done irreparable damage to their political careers.—

The aide added that regardless of the outcome in Massachusetts, Senate Republicans are likely to continue their strategy of delaying and blocking Democratic initiatives. On major issues such as health care last year, Republicans were successful in denying Democrats even a single GOP vote, a tactic that forced Democrats to go it alone and exposed deep fractures in the majority party.

“We would much prefer moderation of Democrat policies that would enable bipartisanship. But despite huge shifts in public opinion, Democrats appear insistent on pursuing a partisan path,— the senior Senate GOP aide said. “Will we oppose partisan back-room efforts to remake our economy and health care system? With every ounce of our being — the American people expect no less.—

Another senior Senate GOP aide said Republicans don’t particularly like being called the “party of no— but acknowledged that the GOP is likely to continue its near-unanimous opposition because Republicans believe the American public is saying no to the Democratic agenda.

“Some of that ‘party of no’ stuff may start to backfire on the Democrats,— the aide said. “Republicans are now viewed as the party more in touch with independent voters, which should send a tremor of fear through— the White House and Congressional Democrats.

But Democrats said they still have time to turn around their fortunes before the rest of the country goes to the polls for the midterm Congressional elections in November.

The key, some said, is to quickly put the health care debate behind them by settling on a bicameral deal and passing it quickly. A rapid time frame for passage may also be needed in order to take advantage of all 60 Democratic votes in the Senate before a potentially victorious Brown in Massachusetts is certified the winner. Temporary appointee Sen. Paul Kirk (D-Mass.) has said he would vote for the bill even if Brown wins today but has not yet been seated when the vote is called.

“The longer we continue with the health care thing, it just ensures more battering and bruising,— a senior Senate Democratic source said. “The sooner we can complete the process on health care, the sooner it can have a comeback in the realm of popular opinion.—

Indeed, Democrats are convinced that once they achieve passage of the bill, the tide will turn in their favor as Americans discover the insurance reforms and consumer protections they have included in the bill.

More importantly, however, Democrats say they need to jettison health care in order to take on the still sagging economy. And a bill designed to encourage job creation is a key Senate agenda item for the four-week work period until Presidents Day.

“What Democrats in Congress need right now is a self-esteem boost,— the Democratic source said. “That will come by finishing up work on a health care bill and moving to a political gimme like the jobs bill.—

But Senate Democrats are starting this work period facing some unpleasant tasks, such as blocked nominations — including the director of the Transportation Security Administration and Federal Reserve chairman — and an unpopular increase in the debt limit.