Senate Republican leaders vowed Tuesday to adjourn sine die before Thanksgiving, even as they spent the day scrambling to shore up support on the energy and Medicare conference reports.

Recognizing the mountain of work ahead of them, including a still unwritten omnibus appropriations bill, Senate GOP Conference Chairman Rick Santorum (Pa.) predicted an exit early next week — although top GOP leaders are still pushing for a Saturday adjournment.

“I suspect we are going to be here into the early part of next week,” Santorum said. “It looks that way.”

Senate Democrats, meanwhile, could not come to any Caucus-wide agreement on how to handle the biggest domestic legislative issues of the day, with one camp proclaiming the Medicare bill the best deal possible and another camp vowing to fight and potentially filibuster the package.

But Democrats specifically did not brook the filibuster issue on either the energy or Medicare bills in their nearly two-hour luncheon.

Democrats seemed particularly concerned about Medicare as they ponder the political dilemma of potentially blocking a vote on an issue they had been pushing for the past six years. In particular, senior Democrats felt that one of their most supportive political allies had yanked the floor out from under them when AARP endorsed the Republican-endorsed Medicare plan on Monday.

Fearful of giving President Bush two huge domestic victories on the eve of the start of the 2004 campaign, Senate Democrats appeared to be more willing to launch what amounted to a filibuster on the energy legislation, which numbers more than 1,500 pages and has produced some scathing attacks from conservative groups as well as Sen. John McCain (R-Ariz.).

“Energy is more attackable,” one Senate Democrat predicted.

But if a filibuster is mounted on energy, it is much more likely to take on a regional rather than ideological dimension, and might require the backing of Republicans such as McCain — who calls it the “leave-no-lobbyist-behind” legislation — and at least a handful of other Republicans (mostly from the Northeast).

Sen. Olympia Snowe (R-Maine), for example, vowed to back a filibuster of the energy bill if McCain or a Democrat such as Sen. Charles Schumer (N.Y.) leads the way in forcing cloture votes.

“I’m likely to vote against cloture,” Snowe said.

Senior Republicans acknowledged that they have their hands full in securing support within their own conference on energy, particularly if they have to reach the 60-vote threshold to move to final passage.

“There are some folks who are clearly against the energy bill,” said Santorum. “I haven’t heard too many people be as hardened against the Medicare bill. I think there are more people who are rather passionate against the energy bill, particularly from the Northeast.”

With the House passing the energy bill Tuesday, Senate Republicans expected to file a cloture motion on the legislation late Tuesday evening, setting up a vote on either Thursday night or Friday morning.

Top aides said the order would then call for either the Medicare legislation or the omnibus to come up, something that hadn’t been decided.

With the omnibus still not completed, however, the momentum could be to move to Medicare first and leave the appropriations measure to go last, particularly as a way to provide extra rewards for lawmakers who are on the fence on Medicare.

The Medicare bill was considered far from a sure thing itself late Tuesday, particularly since a handful of conservative Senators were openly opposing the legislation, in addition to undecided Senators such as McCain and Snowe.

Foremost opposed to the legislation from the right are Sens. Trent Lott (R-Miss.) and Don Nickles (R-Okla.), who combined served almost a quarter century in Senate GOP leadership through 2002.

Sen. John Sununu (R-N.H.) described himself as a “likely” no vote on Medicare, adding that 12 Republicans voted no on final passage in the summer and that close to a handful or more would seriously consider that route this time around.

“I don’t think the improvements were overwhelming,” he said of the Medicare legislation that emerged from a House-Senate negotiation over the weekend.

Sununu left open the idea of several conservatives threatening to join a filibuster led by Sen. Edward Kennedy (D-Mass.), the most outspoken opponent of the package, to at least gain leverage and force the White House and GOP leaders to tweak the legislation more in their favor — or gain a promise to fix things in the future.

“There are ways to address the concerns,” Sununu said.

But clearly the Democrats were faced with a far more flummoxed position, a sharp divide on which way to proceed on both Medicare and energy and their minority leader, Sen. Tom Daschle (D-S.D.), apparently stuck in a political bind with both national and local implications.

One senior Democrat described the AARP endorsement as “a huge announcement.”

“This is a time our Caucus is going to be in a huge disarray just trying to think through and reconcile where all the passion is,” the senior Senator said.

Another Democrat noted that Daschle, who still may face a very difficult re-election battle if former Rep. John Thune (R-S.D.) jumps into the race, is in a precarious position.

Leading a filibuster on a prescription drug plan, no matter how objectionable Democrats may consider the other pieces of the bill like premium supports, could provide Bush and Senate Republicans a major avenue to attack the minority as obstructionist.

At the same time, Daschle could give Thune a major inroad to attack him in a still undecided campaign battle.

One Democratic Senator said the discussion at Tuesday’s lunch on energy and Medicare never reached the level where there was talk of a Democratic leadership-sponsored filibuster.

“I think that was intentional,” the Democratic Senator said. “I don’t think Tom Daschle wants to filibuster officially either one of these.”

This Senator said a filibuster was still a distinct possibility, but not as a leadership-backed position as have been the six filibusters launched by Democrats on Bush’s circuit court nominees.

“If Kennedy wants to do it, [Daschle] is not going to pull him back,” the Democratic Senator said. “But officially he can’t allow one to happen.”

For now, Democrats say that is officially the case, with no final decision having been made. “There’s no plan,” Minority Whip Harry Reid (D-Nev.) said, adding that he’s “terribly mixed” on the Medicare bill.

“We haven’t concluded yet what our strategy will be,” Daschle said before the luncheon, although his opposition to the Medicare package was made clear. It’s not clear whether he will support the energy bill, however, although he said late Tuesday a decision on a caucus-backed filibuster could come “within 24 hours.”

The outrage level from liberal Democrats continued to mount toward the AARP’s decision to endorse the plan, giving Republicans the political cover of the nation’s largest and most respected seniors organization.

Jim Manley, Kennedy’s spokesman, said there was a large backlash against the group, saying that the AARP’s phones were so flooded with angry calls that there were many overflow calls that came into Kennedy’s office.

And Daschle attempted to portray AARP’s board as having staked a lonely position in support of Medicare.

“You have AARP on one side, but you have virtually every other senior organization in the country on the other,” Daschle said.