The White House has decided to fill two seats on the U.S. Court of Appeals for the D.C. Circuit that have been vacant for years, seeking to reverse the long-standing GOP position that the court did not have enough work to justify more judges.

Administration officials confirmed that President Bush intends to name candidates for the 11th and 12th seats on the D.C. Circuit in the next few months. The nominations, together with those of two conservative Washington lawyers chosen by the White House last year, give Bush an opportunity to tilt the ideological balance of a court that is surpassed in influence only by the Supreme Court.

The last two seats on the D.C. Circuit have been empty -- one of them for more than a decade -- because Senate Republicans repeatedly through the 1990s blocked efforts by President Bill Clinton to fill them by contending that the judges would be a waste of taxpayers' money.

A White House official said Bush considers filling those seats to be part of a revised selection method the president announced this fall to try to accelerate the placement of judges on the federal bench.

Under the plan, Bush said he would submit nominations for every judicial vacancy no more than six months after learning of it. For vacancies that existed at the time of his October announcement, the official said, that means Bush will choose candidates by April. The White House has not yet decided who will be named to the D.C. Circuit, but aides are assessing a number of potential candidates, according to several sources familiar with the process.

The decision is already stirring a political squall. Democrats and liberal interest groups say Bush is seeking to load the court with conservatives now that the GOP, having won control of the Senate, will dominate the confirmation process. The move also places Republicans on the Senate Judiciary Committee in an awkward spot, because they are forced either to oppose a popular president of their own party or to abandon their entrenched opposition to adding judges to the D.C. Circuit.

An administration official said Bush "would have done the exact same thing regardless of who won the Senate" in last month's elections. The White House source said the president believes in filling all judgeships that are authorized by law, and noted that Congress reviewed the number of judges on the nation's federal courts this year and did not eliminate any seats at the appellate level.

Judiciary Committee Democrats did not outright oppose the idea of filling the court, but they accused Bush of unfairly trying to create a lopsided bench dominated by his conservative allies. "There is a real danger here with this White House attempting to pack the court with slates of judges who hew to a rigid ideological agenda," said an aide to Sen. Charles E. Schumer (D-N.Y.). The aide said Democrats would "evaluate every tool in our admittedly small toolbox," including possible filibusters, to try to prevent the confirmation of such nominees.

The future of the D.C. Circuit is a microcosm of the tense politics surrounding judicial nominations, the stakes for the nation's laws, and the assertive approach the Bush White House has adopted in seeking to shape the judiciary.

Set at the foot of Capitol Hill, the D.C. Circuit is regarded as the second most powerful court in the country. It routinely handles precedent-setting cases that involve the role of federal agencies, the separation of governmental powers, and sprawling matters of business and trade. At the moment, the court is at an ideological tipping point, with four judges who were chosen by Democratic presidents and four by Republicans. Four seats are vacant.

When Bush announced his first round of judicial candidates in May 2002, he named to the D.C. Circuit a pair of Washington attorneys who are prominent conservatives: Miguel A. Estrada and John G. Roberts. The Senate, led by Democrats for the past 11/2 years, has not confirmed either one, although both are expected to be approved soon. The new judges would be in addition to these two nominees.

Until now, the White House had not entered the controversy over how many judges the D.C. Circuit needs. The administration's stance contradicts the longtime views of Republicans on the Senate Judiciary Committee. Starting in 1995, Sen. Charles E. Grassley (R-Iowa) held a series of hearings to demonstrate why the judiciary should be smaller. At one point, he said of the 11th and 12th D.C. Circuit seats: "Filling either of these . . . would be a waste of taxpayer money." After an 18-month fight, the Senate in 1997 approved one Clinton nominee to the court, but it never voted on two others.

This week, Grassley said that, unless the court's workload has increased, "I'll continue opposing filling those seats . . . just as I have in the past." Another Judiciary Committee Republican, Sen. Jeff Sessions (Ala.), said: "I continue to believe that the caseload of the D.C. Circuit does not justify filling 12 seats on the court."

An aide to incoming Judiciary Committee Chairman Orrin G. Hatch (R-Utah) was more equivocal, saying the committee will "hear the pros and cons against the size of the court, and we'll move forward that way."

Figures from the court indicate that its workload has not increased. The number of new cases filed each year has fluctuated by a few hundred since the mid-1990s, while the backlog has diminished virtually each year, declining from 2,099 in 1995 to 1,270 last year.

Judges themselves have been divided on the question. The most outspoken opponent, U.S. Circuit Judge Laurence H. Silberman, said in a letter to a GOP senator last year that "in my view, we have barely enough work to keep our current complement of [10] judges busy."

This week, Silberman, who is now semi-retired as a senior judge, said: "Anything more than 10 is a waste of government resources" and could hinder the court's ability to make collective decisions.

The White House would not identify contenders for the seats, but administration sources and others who closely follow judicial nominations said the candidates could include Washington attorneys Maureen Mahoney and Peter D. Keisler; and Michael Chertoff, chief of the Justice Department's criminal division.

Staff writer Charles Lane contributed to this article.

Sen. Charles E. Grassley (R-Iowa) has opposed filling all D.C. Circuit seats because of insufficient caseload.An aide to incoming judiciary panel chief Orrin G. Hatch (R-Utah) said the "pros and cons" will be heard.