For the fourth time this year, Senate Republicans failed to force a vote on controversial judicial nominee Miguel Estrada.

Majority Leader Bill Frist (R-Tenn.) vowed to file cloture again and again until Democrats cave and agree to an up-or-down vote on Estrada’s nomination to the U.S. Court of Appeals for the D.C. Circuit.

But Wednesday afternoon Democrats again held strong and beat back a cloture motion, 55-44. The magic number to end debate and proceed to a full vote is 60.

“We now know that a majority of Senators support the nomination of Miguel Estrada,” said Nick Smith, a Frist spokesman. “We’ve had four votes and each time Miguel Estrada gained a majority. Normally that would be enough for him to be confirmed, but unfortunately the Democratic leadership has raised the bar.”

Democrats have said they do not have enough information to vote on Estrada, charging that he was not forthcoming during his Judiciary Committee hearing. Although Democrats are filibustering Estrada’s nomination, they are allowing Senate business to proceed on other matters.

As the battle drags on, however, both sides become less willing to compromise.

Meanwhile, the entire judicial appointee process has grown more contentious.

Frist reiterated his intention Wednesday morning to press ahead with nominees, saying that as Majority Leader he would make more progress on that front than Democrats made when they controlled the Senate last Congress.

Much to Democrats’ chagrin, Judiciary Chairman Orrin Hatch (R-Utah) held a hearing Tuesday on Carolyn Kuhl, nominated to the 9th U.S. Circuit Court of Appeals, without the support of one her home-state Senators.

Historically, both Senators must sign off on a nominee before the committee holds a hearing on the person.

Several nominees have been cleared by the panel but await floor action, including Priscilla Owen, who was rejected last year by the then-Democratically controlled committee but was passed out by this year’s Republican panel.

Frist is also trying to bring Jeffrey Sutton, Deborah Cook and John Roberts to the floor soon.

On Tuesday, the Senate did confirm Timothy Tymkovich to the 10th Circuit. Additionally, Theresa Lazar Springmann was confirmed to the U.S. District Court for the Northern District of Indiana on Monday and James Selna was appointed to be U.S. District Court for the Central District of California on Thursday.