Washington loves a good fight, and Democrats have been giving the media plenty of fodder lately as moderates and liberals battle over the various bills the party has been waiting for decades to enact.

[IMGCAP(1)]So, it’s little wonder that President Barack Obama is bringing the entire Senate Democratic Conference to the White House today for a unity rally disguised as a luncheon.

Just as Obama did when Democrats bristled that centrists were working with Republicans to water down this year’s $787 billion economic stimulus bill, the president is expected to remind Senators of all stripes that the party must stick together to accomplish big things.

Obama, who is expected to try to heal rifts among Democrats on health care as well as make the case for more funding for the popular “cash for clunkers— program, will likely tell his former colleagues that they need to remember that all of their political fortunes — including his — are intertwined.

One senior Senate Democratic aide said the message would be, “We all hang together or we all hang separately.—

Another Senate Democratic aide said the White House and Senate leaders need to clamp down on the intraparty unrest — particularly the noise coming from the liberal flank — to prevent irreparable harm to the party’s agenda.

“What we can’t do is let the party become like the Republican Party. Republicans are in the minority because they’ve become very one-sided,— the aide said, noting Republicans often demanded ideological purity from their Members.

Another senior Senate Democratic aide said leaders have a plan to “make sure our Members leave here in a good place on health care.— The plan, which begins with lunch at the White House, also includes a Wednesday caucus on health care policy and a Thursday caucus on what Senators should say when they go home at the end of the week.

The White House already had to intervene on the House side last week, after a bruising battle between moderates and liberals on the Energy and Commerce Committee nearly derailed that chamber’s health care bill.

Despite extensive hand-holding by the administration, one House aide said the distance between moderate and liberal House Democrats is only getting wider, as each fight piles new resentments onto old ones.

“There was a lot of ill will on both sides when we got out of here, and we’re going to have the same problem when we get back,— the aide said.

Indeed, Energy and Commerce’s ability to pass a health care bill last week does not necessarily portend an easy path forward to the House floor. Last week, four Blue Dog Democrats on the Energy and Commerce Committee struck a compromise with Chairman Henry Waxman (D-Calif.) that allowed the panel to clear a health care bill, but 57 liberals penned a letter to leaders calling the deal “fundamentally unacceptable.—

Liberals have been warning that their votes should not be taken for granted, and some have pointed out that they were the first to compromise on health care by giving up their hopes of a single-payer health care system controlled by the government. Liberal lawmakers now are pushing for a public insurance option to compete with private insurance.

But Speaker Nancy Pelosi (D-Calif.) has continually downplayed internal rifts as a healthy sign of a dynamic legislative process at work. Asked Friday whether she was concerned about the liberal backlash to the Blue Dog compromise, for example, she laughed off the question. “Are you asking me, Are the progressives going to take down universal, quality, affordable health care for all Americans?’ I don’t think so,— she said.

While House Members have an actual health care bill to fight over, Senate Democrats have been wringing their hands over the fact that a bipartisan group of six Finance Committee members are not only eschewing the party’s preferred public insurance option but also seem to be taking their time in coming up with whatever it is they are going to put into their bill.

With little information about the policy proscriptions the bipartisan group is considering, Senate Democratic leaders have struggled to calm nervous Democrats while the Finance negotiators — Chairman Max Baucus (D-Mont.), ranking member Chuck Grassley (R-Iowa), and Sens. Kent Conrad (D-N.D.), Jeff Bingaman (D-N.M.), Olympia Snowe (R-Maine) and Mike Enzi (R-Wyo.) — hold multiple daily meetings. Last week, Baucus pledged to get a deal by Sept. 15 and appeared to have the agreement of the rest of the group. But Enzi pushed back on that Monday, saying he would not abide by any artificial deadlines.

While those meetings are expected to continue in force during the August recess, Finance Subcommittee on Health Care Chairman Jay Rockefeller (D-W.Va.) last week began a campaign that appears designed to undermine the bipartisan Finance effort, from which he has complained of being excluded.

Rockefeller wrote three letters — to the Government Accountability Office, the National Cooperative Business Association and the Department of Agriculture — to try to find out more information about the nonprofit health insurance cooperative model that Finance negotiators seem intent on creating. Rockefeller supports the creation of a public insurance plan which, like the cooperative model, would compete against private insurers.

“I believe the inclusion of a strong public plan option in health reform legislation is a must — it is the only proven way to guarantee that all consumers have affordable, meaningful, and accountable options available in the health insurance marketplace,— Rockefeller said in a statement. “There are real concerns about the potential impact of health care co-ops on consumers, and we cannot afford to hang our hat on any unproven, unregulated, or unreliable model for health insurance coverage.—

Centrists are just as irritated with their more liberal colleagues, saying the rhetoric could kill any attempt to get health care reform this year.

“Political infighting and attack ads make it difficult for Members of the Senate to come together and develop and pass a bill,— said one aide to a moderate Democrat. Liberals “are seeking to polarize people. … I think they’re passionate about what they want, but I hope they will understand that the Senate needs 60 votes to pass a good bipartisan bill. Bipartisanship isn’t just a label. It will help build stronger support in the public’s mind.—

Still, aides said Democrats will eventually come together on health care — particularly once the mystery over the Finance bill is solved.

“At the end of the day, no one is worried that it won’t get done on account of the Democratic Caucus,— said the senior Senate Democratic aide. “Climate change is a whole other ball of wax. … It really cuts more across geographical lines than it does on party lines, and there are some states where that’s going to be a more difficult vote to take.—

Indeed, health care battles may have been making front page news recently, but the climate change issue has already caused serious fractures in the House and threatens to do the same in the Senate, where the debate has barely begun.

Senate moderates are leery of the climate debate, considering conservative House Democrats got badly bruised over the July Fourth recess for supporting that chamber’s landmark package. That backlash precipitated the Blue Dogs’ revolt on health care, which in turn led to the liberal rebellion against the deal leaders struck with the fiscally conservative bloc in the Energy and Commerce panel.

One Senate Democratic aide warned, “If you don’t get health care done in a way that’s bipartisan, then it’s going to be harder to get climate change done. … If we go the partisan route on health care, it’s going to leave a bitter taste in [centrists’] mouths.—

One House Democratic leadership aide said the five-week August break would help soothe nerves frayed by weeks of intense negotiations on energy and health care. “What we’ve shown over the last three years is that we’re able to move past it and get things done,— the aide said.

Others said the challenge of passing both health care reform and climate change legislation has obscured the unity Democrats have enjoyed this year on such issues as the historic regulation of tobacco products, restoring “equal pay for equal work— and expanding children’s health insurance.

“These two bills amount to such heavy legislative lifting, they can overshadow the larger thread that has been in evidence the rest of this session,— said the senior Senate Democratic aide. “To have the kind of victories that we’ve already had this year would have been a big deal … but these other accomplishments aren’t getting their due.—