WASHINGTON -- Miguel Estrada, whose nomination became a flash point for Democratic opposition to President Bush's judicial choices, withdrew from consideration for an appeals court seat Thursday after Republicans failed in seven attempts to break a Senate filibuster.

President Bush called Estrada's treatment "disgraceful." But Senate Democrats said he was a casualty of the White House's insistence on stacking federal appeals courts with conservative ideologues.

"This should serve as a wakeup call to the White House that it cannot simply expect the Senate to rubber-stamp judicial nominees," said Sen. Edward Kennedy, D-Mass., one of the leading opponents to Bush's nominees.

Republicans, however, promised to push forward on other Bush nominees who have been blocked by filibusters.

"Today is a shameful moment in the history of this great institution," said Senate Majority Leader Bill Frist, R-Tenn., in a speech on the Senate floor. "The United States Senate has been denied the right to confirm or reject a brilliant and qualified nominee because of the obstruction of a few."

For Estrada -- who at one point was rumored to be a possible Supreme Court nominee -- the withdrawal ends a two-year waiting game in which his nomination for the U.S. Circuit Court of Appeals for the District of Columbia never got beyond the Senate floor.

"I believe that the time has come to return my full attention to the practice of law and to regain the ability to make long-term plans for my family," he said in a letter to Bush.

Estrada, 41, a private attorney who had never served as a judge, wanted a seat on the D.C. Circuit, which currently is split evenly between Republican and Democratic appointees. The court decides important government cases involving separation of powers, the role of the federal government, the responsibilities of federal officials and the authority of federal agencies.

Democrats argued that Estrada and Bush's other blocked nominees are too conservative to serve on the U.S. Appeals Court, the regional courts that handle federal court appeals around the nation.

They pressed Estrada to make clear his views on issues like abortion rights, but he declined.

The White House refused Democrats' request for the release of internal memos Estrada had written while serving in the office of the solicitor general in the administration of Bush's father.

Republicans, in turn, accused Democrats of bias against Bush's nominees. They sought to portray Estrada, a Honduran immigrant who graduated from Harvard Law School, as a modern-day Hispanic Horatio Alger and accused Democrats of being anti-Hispanic.

The dispute came to head in July when Senate Republicans mounted a weeklong effort to get Estrada and other blocked nominations through.

It takes 60 votes in the 100-member Senate -- which has 51 Republicans, 48 Democrats and one independent -- to break a filibuster. In seven attempts since March, the Republicans never got more than 55 votes for Estrada.

The Senate so far has confirmed 146 of Bush's 196 U.S. district and appeals court nominees since he entered the White House, and the president was blunt Thursday in his criticism of senators who refused to allow Estrada's nomination to go forward.

"Mr. Estrada received disgraceful treatment at the hands of 45 United States senators during the more than two years his nomination was pending," said Bush, who aggressively tried to get the Senate to approve Estrada early this year but had been silent on the issue in recent months.

But Senate Democratic leader Tom Daschle of South Dakota said, "The stumbling block to Miguel Estrada's nomination all along was the administration's refusal to allow him to complete his job application and provide the Senate with the basic information it needed to evaluate and vote on his nomination."

Senate Judiciary Chairman Orrin Hatch, R-Utah, said the GOP would redouble its efforts on other nominations, including Texas judge Priscilla Owen and Alabama Attorney General William Pryor.

"We cannot sit back and let other judicial nominees, like Priscilla Owen and Bill Pryor, suffer the same fate as Miguel Estrada," Hatch said.

Estrada left open the option of accepting another judicial nomination sometime in the future. "I profoundly hope that, at some time in the future, I may be called again to serve my country in some capacity," he said.

Before going home for the day, the Senate on a 94-1 vote approved the nomination of U.S. Attorney Steven Colloton of Iowa for the 8th U.S. Circuit Court of Appeals in St. Louis.

Sen. Ernest Hollings, D-S.C., was the one vote against Colloton, who worked with independent counsel Kenneth Starr investigating Bill and Hillary Clinton and their failed Arkansas land deal, Whitewater, before becoming a U.S. attorney.