New York lawyer Caitlin Halligan, who’s nominated to the U.S. Court of Appeals for the District of Columbia Circuit. (Politico via AP) New York lawyer Caitlin Halligan asked President Obama to withdraw her nomination to the U.S. Court of Appeals for the District of Columbia Circuit. (Politico via AP)

The White House has withdrawn the nomination of Caitlin Halligan to the U.S. Court of Appeals for the District of Columbia Circuit, weeks after Republicans filibustered a vote on her nomination for the second time.

Halligan requested that President Obama withdraw her nomination.

"I am deeply grateful to you for your confidence in me, and your steadfast support of my nomination," she wrote in a letter to the president. "After much reflection, I believe that the time has come for me to respectfully ask that you withdraw my pending nomination from further consideration by the United States Senate."

Read Halligan's letter.

In a statement, President Obama announced himself "deeply disappointed" that Halligan could not get an up-or-down vote.

"This unjustified filibuster obstructed the majority of Senators from expressing their support. I am confident that with Caitlin’s impressive qualifications and reputation, she would have served with distinction," Obama said. "The D.C. Circuit is considered the Nation’s second-highest court, but it now has more vacancies than any other circuit court. This is unacceptable. I remain committed to filling these vacancies, to ensure equal and timely access to justice for all Americans."

Halligan is general counsel for the Manhattan district attorney’s office and previously served as solicitor general of New York state.

Senate Republicans argued that Halligan's work pursuing a lawsuit against the gun-manufacturing industry on behalf of the state showed her to be a “judicial activist” who would not hold a strict view of the Constitution.

Nominations to the D.C. Circuit get special scrutiny because the court has jurisdiction over much of the federal government. It has also been a reliable steppingstone to the Supreme Court; four of the nine current justices served on this bench. Both parties have treated nominees to the D.C. Circuit with extreme caution.

Senate Judiciary Committee Chairman Patrick Leahy (D-Vt.) declared it "a shame that narrow, special interests hold such influence that Senate Republicans for two years blocked an up-or-down vote on her confirmation." Halligan would have been "an outstanding judge," he said.

Liberals disappointed in the Senate for not paring back the filibuster pointed to Halligan's fate as an example of the chamber's dysfunction.

Her withdrawal is "still another indication, as if any were needed, that Senate Democrats need to revisit Senate rules reform," said Nan Aron, president of the progressive Alliance for Justice.

Each side has repeatedly switched its position on filibusters depending on the political circumstances and which party controls the White House. A decade ago, during the administration of President George W. Bush, Senate Republicans criticized Democratic filibusters of appellate court nominees and tried unsuccessfully to change the rules to outlaw filibusters on judicial selections.

Halligan is the second of Obama's appellate court nominees to quietly withdraw from consideration after a Republican filibuster. The first was Goodwin Liu, in 2011. Both were mentioned as potential nominees to the Supreme Court.

There are four vacancies on the D.C. Circuit court. The nomination of Sri Srinivasan, Obama's deputy solicitor general, has not yet gotten a vote in the Senate Judiciary Committee. In his first term, Obama did not get a single nominee onto the court. Overall, eighteen of Obama's judicial nominees are currently awaiting confirmation.

Philip Rucker and Paul Kane contributed to this report.