For the second time in two months, the Senate Judiciary Committee postponed a vote Thursday night on President Bush's nomination of Claude A. Allen, a prominent Virginia conservative, for a seat on the U.S. Court of Appeals for the 4th Circuit in Richmond.

A standoff between the White House and Maryland's two Democratic senators, Barbara A. Mikulski and Paul S. Sarbanes, means that, barring a last-minute deal, the nomination is most likely dead for the year. The Senate by custom rarely acts on court appointments after the August recess during a presidential campaign, but committee Chairman Orrin G. Hatch (R-Utah) expressly has not ruled out the possibility of a vote.

After the committee failed to achieve a quorum Thursday, Hatch put off the vote and said he would attempt to work with the White House on addressing the Maryland senators' claim that the 4th Circuit -- which includes Maryland, Virginia, West Virginia and North and South Carolina -- has historically apportioned seats according to each state's population.

Maryland had three judges on the 15-seat court before Francis D. Murnaghan Jr. of Baltimore died in 2000.

"Senator Hatch indicated that the Maryland senators raised concerns that need to be closely reviewed. He continues to work in good faith," Hatch spokeswoman Margarita Tapia said, adding that the chairman spoke with administration officials Thursday.

Hatch and other Republican senators have publicly sympathized with Mikulski and Sarbanes, noting the potential loss to the senators' state.

Before nominating Allen last year and again in January, after the Senate failed to act, White House officials proposed at least two Maryland residents for the seat, but Mikulski and Sarbanes found them unsuitable, according to participants in the discussions.

White House spokeswoman Erin Healy said she was unaware of any change in the administration's position on Allen.

"The president . . . feels that he is well qualified and would make an excellent addition to the bench," Healy said. "At this point, the president supports Mr. Allen's nomination."

Bush and Senate Democrats have been locked in a war of wills for much of his tenure, continuing a recent history of fierce partisanship over judicial nominations. The sides struck a deal earlier this year in which Bush agreed to make no recess appointments -- which are not subject to Senate confirmation -- and Minority Leader Thomas A. Daschle (D-S.D.) agreed to allow 25 noncontroversial nominations to reach the floor for confirmation. Allen's was not among them.

Even if Allen's nomination were approved by the panel, Sarbanes spokesman Jesse Jacobs said, Maryland's senior senator "will forcefully oppose the nomination if it comes to the Senate floor," shorthand for a possible filibuster.

"This is a Maryland seat, and a Marylander should have been nominated for it," Mikulski said.

Allen, deputy secretary of the U.S. Department of Health and Human Services, was Virginia's secretary of health and human resources under Gov. James S. Gilmore III (R).

As an aide to North Carolina Sen. Jesse Helms (R) in the mid-1980s, he sparked controversy by referring once to homosexuals as "queers." Allen told the committee he meant no insult to any individual or group.

The American Bar Association's judiciary review committee rated Allen in the bottom fifth of federal nominees in the past two years. A majority graded him "qualified" ("well qualified" is the top rating), partly because he has not served as a judge or practiced law for at least 12 years. Allen did serve as a clerk for the U.S. Court of Appeals for the District of Columbia.

Virginia Sens. John W. Warner (R) and George Allen (R) have stood by the nominee. They say his Senate confirmation as a deputy Cabinet secretary in 2001, and his nomination by President Bill Clinton to the African Development Foundation, attest to his worthiness for the job.

"As a result of his unique experience at the state and federal levels of government, Secretary Allen is well qualified for a judgeship on this important court," Warner said.

Sen. Allen said, "The Senate should be permitted to vote up or down on the nomination of Claude Allen, and the Democrats should stop their obstructionist tactics."

Claude A. Allen, a Bush nominee to the federal bench, appears on Capitol Hill last fall with wife Jan and son Alexander.