The chairman of the Senate Judiciary Committee, Patrick J. Leahy (D., Vt.), had been pushing for a vote on Liu, who had been nominated three times for the appellate post.
Republicans have made Liu their prime example of a judicial nominee who, in their view, has been so unabashedly liberal in his writings and statements that he does not deserve an up-or-down vote.
The politics were reversed in 1987, when Democrats defeated Republican Supreme Court nominee Robert Bork by citing his conservative writings.
In both cases, opponents argued the nominees would take their views to the bench, allowing those views to trump the Constitution.
To most Democrats and liberal backers, Liu is the type of nominee they want for a lifetime appointment on the federal bench. He supports liberal social issues such as gay marriage and affirmative action. He was given a top rating of unanimously well-qualified by the American Bar Association. He was a Rhodes scholar and clerked for Supreme Court Justice Ruth Bader Ginsburg.
To most Republicans and conservative allies, he's a judicial activist who made insulting remarks about the Supreme Court nominations of John G. Roberts Jr., now the chief justice, and Samuel A. Alito Jr.
Two senators favoring a continued filibuster were John McCain (R., Ariz.) and Lindsey Graham (R., S.C.). Both were part of a group of 14 senators who previously pledged not to filibuster judicial nominees except under extraordinary circumstances.
"The nomination of Mr. Goodwin Liu does rise to a level of extraordinary circumstances and therefore McCain will seek to filibuster the nomination," McCain's office said in a statement Wednesday.
Graham said: "His outrageous attack on Judge Alito convinced me that Goodwin Liu is an ideologue. Goodwin Liu should run for elected office, not serve as a judge. Ideologues have their place, just not on the bench."
Sen. Chris Coons (D., Del.) said: "The notion that somehow Professor Liu is an ideologue . . . is belied by his actual record."
Coons added: "Why on earth this record of this exceptionally qualified man would justify a filibuster is utterly beyond me and suggests that unfortunately we've been mired in partisanship."