As Senate leaders descended onto the chamber floor Thursday for a second day of debate, some moderate lawmakers indicated a compromise regarding a possible showdown over judicial filibusters could come sometime this day.

Asked to clarify an earlier remark to FOX News that the Senate "could see a compromise within an hour or by the end of the day," Sen. Ben Nelson, D-Neb., said that the "situation is very fluid" and the options include either a quick conclusion or no deal at all.

"Sometimes these negotiations and these consultations and meetings seem endless but you're not able to really judge how long something's going to take," Nelson told FOX News later Thursday. "I don't know if you're going to have it within the next hour or at all, but you've got to continue to talk and work through language and work through concepts."

Another meeting has been scheduled for 3:30 p.m.

Nelson is one of the dozen or so key lawmakers who have been hammering out some sort of deal to avoid the so-called "nuclear option" from being used to end judicial filibusters.

Senate Minority Leader Harry Reid said Thursday that he has talked to a number of senators on both sides of the aisle who are working on this compromise and they have not been able to work something out yet.

"The fact is they haven't been able to ... and a number of them contact me on a regular basis," Reid said.

But Nelson did tell FOX News that the group of senators have "fairly sophisticated ideas" down on paper and that some of those ideas "could be abolished ... some could be reconstructed ... edited ... each word is very important" so that there's no wiggle room for interpretation.

Senate Majority Leader Bill Frist of Tennessee said Thursday that barring a deal, he will call a vote next week on whether Republican senators are willing to let the minority Democrats continue to block the White House's judicial appointments through filibusters.

"The principle is that judicial nominees with support of a majority of United States senators deserve a fair up-or-down vote on the floor of the United States Senate," Frist said.

Watch the latest update on the filibuster fight from FOX News by clicking in the video box.

Democrats argue that doing away with the filibuster has drastic ramifications and that it must be retained to give the minority a debate tool to voice dissent.

"The Senate is not a rubber stamp for the executive branch," Reid said Thursday on the Senate floor, when arguing that President Bush and the GOP were trying to "rewrite the Constitution and reinvent reality" in their push to confirm controversial judicial nominees.

He added: "We're the one institution where the minority has a voice and the ability to check the power of the majority. Today, in the face of President Bush's power grab, that's more important than ever."

Building the 'Trust Factor'

Frist and Reid opened formal debate Wednesday and continued Thursday on Texas jurist Priscilla Owen (search) — the nominee that will test the Democrats' ability to continue blocking judges with filibusters. Owen is up for a position on the 5th U.S. Circuit Court of Appeals in New Orleans.

Reid was planning to use his power to deny committees and subcommittees the right to conduct business until after 11:30 a.m. EDT — two hours after the Senate comes into session for the day, as he did Wednesday morning.

But Sen. Richard Lugar, R-Ind., chairman of the Senate Foreign Relations Committee, announced that he had been informed that the committee had been given permission by a unanimous consent proposal on the Senate floor to allow to continue a hearing on Iran's weapons proliferation with Undersecretary of State for Political Affairs Nick Burns.

Nonetheless, Senate Republicans intend to organize a press event Thursday with the handful of committee chairmen, whose scheduled committee meetings will likely be affected by Reid's action, to demonstrate that Reid is obstructing business.

Sen. David Vitter, a Republican freshman lawmaker from Louisiana, is one of the senators who will protest the use of the Democrats' judicial filibuster, which he said has "ground everything to a halt." Vitter said he got a good feel for what his constituents think of such Senate impasses while he was campaigning around the state last year.

"What I heard over an over and over is that we need to do the people's business, we need to move beyond this bitter partisanship and obstruction and do the people's business. Give these people and up-or-down vote then move on to key issues like energy," Vitter told FOX News.

"What Democrats want to do is forestall the results of the election … we have elections in this country for a reason — to put people in office and allow them to govern."

The Democrats' move is an effort to show Republicans that they are more than willing to make good on grinding Senate business to a halt if the so-called "nuclear option" (search) was employed, which means the use of judicial filibusters will be banned.

"I think it would have consequences for the Democratic leadership in the United States Senate if they continue to hold up progress on the important priorities for the American people," White House spokesman Scott McClellan warned Wednesday. "The American people elected us to get things done. The American people want to see us work together on important priorities."

Because Democrats already have prevented final votes on 10 of Bush's first-term appeals court nominees, and have threatened to do the same this year to seven the president has renominated, Republicans are considering doing away with the filibuster — or endless debate — in order to get things moving in the chamber and get an up-or-down vote on the nominees. The filibuster can be overcome only by a majority of 60 votes or more in the 100-member Senate.

But most lawmakers want to avoid the nuclear option altogether so hope on a deal remains. However, in that deal, Democrats say they want to reserve the right to filibuster a judicial nominee under what they deem "extraordinary circumstances." Nelson said Thursday that senators have reached a general comfort level in what is defined as extraordinary circumstances.

Nelson said the biggest progress throughout the course of these talks is the building of trust but noted that a few senators who weren't present at Wednesday's talks, such as Democratic Sens. Kent Conrad of North Dakota and Robert Byrd of West Virginia, were in the negotiating room Thursday.

"You build your trust in these [negotiations] ... and I think that's been an improvement since day one ... the trust factor is increasing... but this is a difficult negotiation... each side is giving up something," Nelson told FOX News.

While Bush has made clear he wants an up-or-down vote for all his judicial nominees, a White House source told FOX News "there is no active lobbying" on behalf of the president in the rules debate. Such lobbying, the source said, could lead to a "huge outcry" by Republicans as well as Democrats, that the Executive Branch is trying to affect a Senate rules change. The source said "it would not be productive to getting an up-or-down vote for the president's nominees."

Prelude to Supreme Court Fight?

The senators seen going in and out of those sessions during the day included Republicans Graham, Mike DeWine of Ohio, John Warner of Virginia, John McCain of Arizona, Susan Collins of Maine, Mike DeWine of Ohio, Lisa Murkowski of Alaska and Democrats Salazar, Nelson of Nebraska, Mary Landrieu of Louisiana, Joseph Lieberman of Connecticut and Mark Pryor of Arkansas.

"This whole debate, for me, is about the Supreme Court," said Sen. Lindsey Graham, R-S.C., one of the negotiators. "What do you do with the next level? Can you get the Senate back to more of a normal working situation?"

While lower court nominees are at the forefront of the argument, the clear subtext of the debate is how the Senate will treat a future Supreme Court nominee from President Bush.

While the Supreme Court has no current vacancies, court watchers expect a retirement before the end of Bush's presidency. Chief Justice William Rehnquist (search), who is 80, is fighting thyroid cancer, and some analysts are taking odds that he could make a statement as early as this summer.

"When a Supreme Court position becomes open the issue will be, will it require 60 votes to approve a Supreme Court judge — something that's never required — or will it be a majority vote? Must we have a super majority?" said Sen. Sam Brownback, R-Kan.

One of the deals being worked on would have the Senate confirming Owen, California judge Janice Rogers Brown (search) — a California Supreme Court justice nominated to the Circuit Court of Appeals for the District of Columbia —and former Alabama Attorney General William Pryor (search), with Idaho lawyer William Meyers (search) nomination scuttled. As part of that deal, two Michigan nominees, David McKeague (search) and Richard Griffin (search), would be confirmed, while a third nominee — Henry Saad (search) — would be jettisoned.

A fourth Michigan judge, Susan Neilson (search), also would be confirmed. She has not been filibustered by Democrats in the past.

Senators are still negotiating that part of the deal and it is subject to change, aides said.

Under the latest Republican-crafted proposal, both sides would have to operate on "good faith." Republicans would be bound not to ban judicial filibusters only if Democrats forswear judicial filibusters except for extraordinary situations, aides said.

But that plan doesn't sit well for some.

"I don't like that plan at all because I think that's where we're deciding who's going to get a vote and who's not," Sen. Richard Shelby, R-Ala., told FOX News Thursday morning. "I believe all of these nominees — they've been vetted, they've come out of committee, they're extremely qualified and we ought to vote them up-or-down."

Frist and Reid are closely monitoring the developments. But Reid said his party would fight to retain what power it still had in a Washington run by a Republican president and GOP houses of Congress.

"If Republicans roll back our rights in this chamber, there will be no check on their power," said Reid. "The radical right wing will be free to pursue any agenda they want. And not just on judges. Their power will be unchecked on Supreme Court nominees, the president's nominees in general and legislation like Social Security privatization."

The Senate has approved 208 Bush judicial nominees (search), including 35 appeals court judges.

Just a majority of senators present are needed to approve a nominee once a vote is called in the Senate, and only 50 if the vice president, who breaks ties, votes in favor of a nominee.

FOX News' Julie Asher, Wendell Goler, Molly Hooper and Liza Porteus and The Associated Press contributed to this report.