By Thomas Ferraro
WASHINGTON (Reuters) - U.S. Senate Democratic Leader Harry Reid is again threatening to change the rules to strip Republicans of their ability to block President Barack Obama's nominees - and this time he may do it, perhaps as early as Thursday, aides said on Wednesday.
To prevail, Reid will need 51 votes in the 100-member Senate, which Obama's Democrats hold, 55-45.
"I think Harry will do it if he has the votes, and I think he will have the votes," said Democratic Senator Benjamin Cardin of Maryland.
But with a number of Democrats reluctant to change the rules, aides said it was unclear if Reid will have the votes. As of Wednesday, he was close, within one or two, they said.
The proposed rule change would reduce to 5l from the current 60 the number of votes needed to end procedural roadblocks known as filibusters against nominees for the executive branch, including department heads, and all federal courts, except the U.S. Supreme Court, aides said.
The rule change would not cover filibusters against legislation, aides said.
Over the years, both parties, when in the majority, have threatened to change the rules to strip the minority of their power to filibuster nominees.
But in the past, both sides have backed off. Many senators have not wanted to upset traditions in the Senate, which has long been known as "the world's most deliberative body."
Over the years, senators in the majority have been hesitant to change the rules because they realize this could hurt them once the other party wins Senate control.
With Congress's approval rating in single digits and no indication Republicans will compromise with Obama on much of anything, Reid figures he has nothing to lose, aides said.
They added that Republicans will likely retaliate if Reid changes the rules by perhaps trying to tie the Senate in procedural knots and slow action on legislation favored by the administration.
But Reid assumes that voters, who polls show are disgusted with the gridlocked Congress, won't be upset if he changes the rules to get some things done, at least on nominations, the aides said.
Reid also figures that if doesn't change the rules, that increasingly anti-compromise Republicans will do it when they win control of the Senate, which could happen in next year's election, the aides said.
In the meantime, Reid could change the rules and win confirmation of a number of Obama's second-term nominees, including three blocked in recent weeks to the U.S. Circuit Court of Appeals for the District of Columbia.
The D.C. Circuit is considered the country's second most important court, behind only the U.S. Supreme Court. One of 13 circuit courts, the D.C. court handles cases involving federal regulations and the separation of powers between Congress, the president and the courts.
Republicans accuse Obama of trying to pack the D.C. Circuit to win favorable rulings, and that the court doesn't have a big enough workload to merit any more judges.
Democrats reject the complaints, and say that Obama has a responsibility to fill the court's three vacancies with qualified nominees.
Robert Wilkins, a district court judge since 2011 who received the American Bar Association's highest rating, was the most recent nominee to the D.C. Circuit to be filibustered. He was stopped on Monday on a nearly party-line vote of 53-38.
The next day, Reid said, "I'm at the point where we need to do something to allow the government to function."
Reid threatened to change the rules in July. But he backed off after a bipartisan deal was reached to fill seven executive-branch posts. He also threatened to change the rules in January, but again backed off after another bipartisan deal was reached.
Republican Senator Richard Burr of North Carolina said on Wednesday, "I'm tired of the threats."
"If he's going to do it, then go ahead and do it. If he's not going to do it then quit talking about it," Burr said.
"I think from all the indications I've heard from the other side, it should be done tomorrow afternoon."
Republican Senator Susan Collins of Maine said she believes Reid has decided to change the rules. "I hope he'll reconsider," she said.
(Additional reporting by Richard Cowan; Editing by Eric Walsh)