The first of President Bush's blocked judicial nominees advanced to the Senate on Thursday, setting up a showdown over filibusters that could shut the Senate down.

The Judiciary Committee, on a 10-8 party-line vote, sent the nomination of former Interior lawyer William Myers (search) for the 9th U.S. Circuit Court of Appeals (search) to the full Senate for approval. The Senate is expected to consider the nomination after its Easter recess.

"The Myers nomination is likely to be used as the trigger for the nuclear option," said Sen. Charles Schumer, D-N.Y., referring to a threatened Republican effort to change Senate rules.

Myers was one of 10 nominees to U.S. Appeals Courts — the regional courts one step below the Supreme Court — who were blocked in the last Congress by Democrats through filibuster threats. The Senate confirmed 204 federal trial and appellate judges during Bush's first term.

With a Senate comprising 55 Republicans, 44 Democrats and a Democrat-leaning independent, Democrats still have the 40 votes necessary to uphold a filibuster. But Republicans are threatening to change the Senate rules to prevent Democrats from blocking judicial nominations.

That has been dubbed the "nuclear option" (search) because some say it would blow up Senate relations. Some supporters call it the "constitutional option" because they say forcing confirmation votes will return the Senate to its constitutional responsibility to advise and consent on judicial nominees.

Senate Democratic leader Harry Reid of Nevada said Tuesday that if the Republicans try to eliminate judicial filibusters, Democrats will retaliate by slowing down or stopping Senate business through procedural maneuvers.

The issue is paramount because Chief Justice William Rehnquist is suffering from thyroid cancer. Democrats and Republicans — anticipating that President Bush will have at least one vacancy to fill on the high court — are girding for a monumental confirmation battle.

In lieu of an immediate Supreme Court vacancy and nomination, Myers will be the first test of both sides' resolve.

Republicans say Myers, who is now a private lawyer in Boise, Idaho, would make a good judge on the 9th U.S. Circuit Court of Appeals in San Francisco, which many of them say is the most liberal of the regional appeals courts.

"Mr. Myers has an extensive record, and you can find some fault with him. But I think that on the totality it is a very good record. He is a distinguished lawyer," said Senate Judiciary Chairman Arlen Specter, R-Pa., who pointed out that the Senate confirmed him to be the Interior Department's top lawyer.

Specter chose Myers as the first appellate nomination to move through the Senate because he thought he could get several Democrats to vote for his confirmation. Democratic Sens. Joseph R. Biden, Jr., of Delaware and Ben Nelson of Nebraska joined with Republicans last July to try to break the filibuster on his nomination.

But Democrats are calling Myers the most anti-environment nominee Bush has sent to the Senate for confirmation.

He represented mining and cattle interests before serving as the Interior Department's top lawyer from 2001-2003. Opponents contend his past writings and decisions suggest he would side with those interests as a judge.

"Mr. Myers is neither qualified nor independent enough to receive confirmation for a lifetime appointment to this federal circuit court," said Sen. Patrick Leahy of Vermont, the top Democrat on the committee. "His nomination is the epitome of the anti-environmental tilt of so many of President Bush's nominees and policies."