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In the war over President Bush's judicial nominees, Republicans call Democratic efforts to filibuster candidates an unprecedented obstruction of the president's discretion to appoint judges to the bench. Conversely, Democrats argue that the use of filibusters for judicial nominees is nothing new.

Democrats point to the 1968 filibuster of Supreme Court Justice Abe Fortas (search) in response to his nomination to become chief justice. Republicans counter that unlike Bush's current nominees, Fortas never had majority support despite being appointed by a Democratic president for approval by a Democratic Senate.

President Lyndon Johnson (search) nominated Fortas, his longtime confidant, to the Supreme Court in 1965. Johnson relied on Fortas as a legal and political adviser. Their closeness was easily apparent in a phone call between Johnson and Fortas moments after the Senate Judiciary Committee unanimously approved his Supreme Court nomination.

"I want to congratulate you, damned if you don't sew them all up," Johnson told Fortas. "It's just no fair, a unanimous vote, that looks a little dangerous to me."

In the Aug. 10, 1965, tape now available to the public for listening at the Johnson Presidential Library, Fortas joked that he too was relieved that the confirmation was unanimous.

"I'm so grateful and I guess it would not have been very pleasant if it had not been unanimous," Fortas said, to which Johnson responded: "Mighty proud of you, that's all I wanted to say."

When Johnson sought to elevate Fortas to the chief justice of the court in June 1968 to replace retiring chief Earl Warren (search), the late president calculated that he had just enough votes to confirm Fortas so long as Senate kingpins Richard Russell, a Democrat of Georgia, and Everett Dirksen, a Republican from Illinois, stayed on board.

But their support and that of other senators wavered after Fortas acknowledged that he had briefed Johnson on secret court deliberations, attended White House staff meetings, lobbied senators to back the Vietnam War and accepted a teaching stipend equal to 40 percent of his court salary.

In September of 1968, conservative Democrats and Republicans filibustered Fortas. Democrats and their backers cite that event as proof that judicial filibusters are neither new nor against the rules.

"Fortas is a great precedent in terms of showing that filibusters have been used, not frequently, but regularly by Republicans and Democrats over the last 35 years or so," said Ralph Neas, president of People for the American Way.

Republicans and their supporters say the Fortas case proves nothing because when Johnson sought to break the filibuster, Fortas could not muster even a simple Senate majority.

"He got 47 votes, he couldn't get 50 for that on that day. Later that day, he asked Johnson to withdraw his name," said former White House counsel C. Boyden Gray.

Democrats say many lawmakers skipped the vote to break the filibuster but would likely have backed Fortas in an up-or-down vote.

"If he didn't have 51 votes, the Republicans wouldn't have filibustered him," Neas said.

Republicans point to a 1968 letter signed by some of the nation's top lawyers and law school deans of the time arguing that judicial filibusters had no basis in Senate history or the U.S. Constitution.

"Nothing would more poorly serve our constitutional system than for the nominations to have earned the approval of the Senate majority but to be thwarted because the majority is denied a chance to vote," reads the letter.

Republicans argue that contemporary Democratic filibusters do just that.

"Listen to what we say on our side. There has never been a judicial filibuster of a nominee to the appeals court, to the Supreme Court or for that matter to the district court that enjoyed a majority support in the Senate," said Senate Majority Whip Mitch McConnell, R-Ky.

The debate over whether Fortas faced a meaningful filibuster doesn't help resolve the current standoff over Bush's judicial nominees. Like many elements of the debate, neither side can agree on the facts or their historical relevance.

Click in the box near the top of the story to watch a report by FOX News' Major Garrett.