Just over a year after confirming President Bush’s second nominee to the Supreme Court, many Senators say they are holding their breath that they won’t have to entertain another high court vacancy this Congress, anticipating a battle royal that likely would bring the narrowly divided chamber to a partisan standstill.

“I hope we don’t have one,” said moderate Sen. Mark Pryor (D-Ark.). “If we have to, we have to, but I really hope we don’t.”

Democrats and Republicans alike agree that the thought of considering a third Supreme Court selection over the next two years is difficult to swallow, especially given the current political landscape that has thrust the Democrats into a narrow majority against a lame-duck Republican White House. What’s more, the politics of the 2008 election has already started to take hold of Capitol Hill, influencing the schedule and the legislative agenda.

“It would certainly suck all the oxygen out of the air,” said Sen. John Cornyn (R-Texas), a conservative Bush ally who sits on the Judiciary Committee, which considers nominations.

Senators said any high court vacancy over the next two years could easily overtake the chamber’s business, but the closer the 2008 elections get, the more problematic it will be for the two parties to consider, find consensus and confirm a new justice. In fact, most Senators said it might be impossible for Bush to successfully usher in a new appointment under the spotlight of a presidential election and with the clock ticking on end of his term.

“First, I really don’t think it’s going to happen,” said Sen. Jon Kyl (Ariz.), the No. 3 GOP leader. “But secondly, it really depends on the timing. If it happens a year from now, forget it.”

“An opening in the near term would precipitate a significant debate,” said Democratic Policy Committee Chairman Byron Dorgan (N.D.). “Most of us fervently hope this president doesn’t get a third appointment.”

Hopes aside, the possibility of another opening remains. Four of the nine justices have surpassed their 70th birthdays, and one of them, Associate Justice John Paul Stevens, just turned 87. Associate Justice Ruth Bader Ginsburg, 74, appointed by President Bill Clinton, successfully battled colon cancer eight years ago.

Bush successfully shepherded two justices through the GOP-controlled 109th Congress, first with now-Chief Justice John Roberts and early last year with the more controversial now-Associate Justice Samuel Alito. The two picks were widely praised in GOP circles for their legal and conservative credentials, while liberals cringed at the selections, as they feared the installments would shift the overall direction of the Supreme Court.

The slant of the Roberts court has started to come into view in recent weeks with a ruling narrowly upholding a federal ban on partial-birth abortion. The court is now considering another high-profile case over whether to overturn a key piece of the 2002 Bipartisan Campaign Reform Act.

Both Senators and outside observers believe Bush would try to install a third conservative-leaning justice to the Supreme Court, and in all likelihood, that selection would replace one of the more senior, liberal-leaning justices. Experts agree the president would most likely tap a female or minority to fill any opening and refer to a working list from his previous selections.

Among the possibilities are Diane Sykes, a federal judge on the 7th U.S. Circuit Court of appeals, Edith Brown Clement or Priscilla Owen, both of whom sit on the 5th U.S. Circuit Court, and Maura Corrigan, a Michigan Supreme Court justice. Other names that surfaced before Alito was tapped included Emilio Garza of the 5th U.S. Circuit Court and Michael Luttig and J. Harvie Wilkinson III, both of the 4th U.S. Circuit Court.

White House officials acknowledge any Supreme Court opening now would be an extremely heavy lift, noting that the confirmation of a justice to a lifetime appointment even under the best of circumstances is a tough sell. The best and perhaps only chance of winning a confirmation over the 110th Congress, they say, would be to offer a nominee with impeccable credentials, who even with a conservative legal bent couldn’t be deemed ill-qualified by the Democratic majority.

“A Supreme Court nomination in any environment, in any situation, is never a breeze,” said one White House aide. “It’s exhaustive from our standpoint. The last time, we took everything off the agenda … it was all hands on deck.”

This administration official added that the White House challenge would be finding a candidate “who is phenomenally qualified and a true constitutional and legal master.”

“It’s never easy,” the official said. “It’s the most difficult lift. Putting in a new vice president would probably be easier.”

A nomination fight would put Senators from both parties in a vise. Conservative judicial groups would up the pressure on Bush and the GOP to tap a like-minded justice, while liberal base organizations would keep the heat on Democrats to push back against any nominee who would further shift the court to the right.

“There are huge, huge ramifications,” said Sen. Ron Wyden (D-Ore.).

Democrats have recently renewed their criticism of Alito, who replaced the more moderate Associate Justice Sandra Day O’Connor, while the scores of 2008 presidential candidates — including four sitting Democratic and two Republican Senators — already have put the issue squarely atop their political platforms. Stalling a Bush nomination for just a few months could mean the difference between a conservative or liberal-leaning justice, depending on the outcome of the next presidential election.

Because of that, many Senators wonder whether the chamber could advance any Supreme Court nominee this Congress. With a 51-49 Democratic majority, the margins are too narrow to ensure either side a smooth victory. Add to the challenge the fact that the Judiciary Committee, the first test for any Supreme Court hopeful, is one of the most partisan panels in the Senate.

“The fight might be shorter — the nominee wouldn’t get out of committee,” suggested a senior Democratic Senate aide.

Even so, Republicans believe the Democrats would face insurmountable pressure to allow an up-or-down vote on a Bush selection and could stall a vote only for so long without facing public backlash. An opening on the court could leave the bench temporarily at just eight justices, setting the stage for split decisions or even worse, a virtual slowdown of rulings.

Curt Levey, executive director of the conservative Committee for Justice, said he has no doubt that Bush will follow his own example, set with Roberts and Alito, and tap another conservative nominee. Still, Levey has no illusions about how great the political pressures will be if a vacancy occurs over the next two years.

“Being right in the middle of a presidential year, it would be enormous,” Levey said. “But even if it happens this year it would be enormous.”

Sen. Richard Burr (R-N.C.), a conservative first-term Senator, said he believes Democrats would have to ultimately allow an up-or-down floor vote on a nomination of such consequence, referring back to the 2005 showdown between the parties over the movement of Bush’s judicial picks. The issue precipitated a standoff between the parties and led to the formation of the bipartisan “Gang of 14,” a group of Senators who struck a deal allowing Senate votes on some controversial nominees while keeping the minority’s right to filibuster intact.

“I truly do believe the American people would demand action on it,” Burr said of a Supreme Court opening. “They see the Supreme Court as a final determining factor. I don’t know that they would hear of anything other than a court that functions.”

Democrats say they would hope that Bush would review the Congressional climate and put up a judicial pick that could meet both parties’ standards, shying away from a conservative firebrand as seen in Alito. Still, Democrats say they are realistic about those prospects, given Bush’s judicial trend and his desire to round out his legacy by placing a conservative brand to the highest court.

“It would have to be a moderate,” said Sen. Ken Salazar (D-Colo.), a centrist who served in the Gang of 14. “He doesn’t have the votes to get a conservative nominee. That’s the only possibility for him to get a Supreme Court justice confirmed. Otherwise, it won’t happen.”