Senate Republicans are charging Democrats with embracing the “nuclear option” in their move to alter the filibuster.

Stepping up their defense of the parliamentary maneuver and looking to claim the political high ground, Republicans are attempting to brand Senate Majority Leader Harry Reid’s (D-Nev.) effort with the same rhetoric Democrats used in 2005, when the then-majority GOP Conference threatened to change the rules. It was an attempt to prevent Democrats from filibustering President George W. Bush’s judicial nominees, and at the time, Republicans defended the effort by calling it the “constitutional option.”

“It’s exactly the same move,” said a senior Republican Senate aide, who added that the “nuclear option is a radical” departure from regular order.

Reid has vowed to do away with filibusters on procedural votes if Democrats hold the majority in the November elections. Senate Republicans oppose the idea, and in particular they take issue with Reid’s threat to change the rule through a majority vote of just 51 Senators. Changes to the Senate rules typically occur on a two-thirds, or 67-vote, threshold, but the chamber’s rules allow for changes to be made with the consent of 51 Members if those changes are voted on at the beginning of the Congressional session.

Overcoming a filibuster requires 60 votes, and Reid contends that Republicans have abused the tactic.

If the Democrats keep control of the Senate on Nov. 6, it is unclear whether they will have the 51 votes they would need to implement Reid’s proposal. Some veteran Democrats, as well as those from Republican-leaning states, could resist the weakening of the filibuster. But Sen. Tom Udall (D-N.M.) believes his party is close. Udall, elected to the Senate in 2008, helped lead an effort to reform the filibuster rule in 2011 at the beginning of the current Congressional session. Senate leaders blocked him.

“I’ve watched with great interest [Reid’s] exchanges with the Republican leader and I’ve had some private conversation with him that I am not going to get into,” Udall said. “I think we could be very close to 51 votes right now.”

Republicans compare the move to change Senate rules to the fight over Democratic filibusters of judicial nominations in 2005, when then-Senate Majority Leader Bill Frist (R-Tenn.) was considering a change in Senate rules to eliminate use of the filibuster to prevent judicial confirmation votes.

Opponents of Frist’s maneuver dubbed it the “nuclear option,” but he and other proponents called it the “constitutional option.”

The issue was settled by the “gang of 14,” a group of seven Democrats and seven Republicans who agreed not to vote with their party on filibustering judicial nominees except in the case of extraordinary circumstances as defined by each individual Senator.

“What you called it depended what side you were on,” a Senate GOP aide said. The Democrats’ plan is “exactly the same move that drew the gang of 14 together.”

The aide said the issue is not expected to get any play in Congressional campaigns but said that despite being an “internal Senate issue,” it is still important, as making the change would remove the minority’s leverage to influence and alter legislation. Going forward with the change would impinge on a Senator’s ability to effectively represent their constituents, the aide said.

The aide argued that when Senate Democratic leaders allow votes on GOP amendments, Republicans decline to filibuster and legislation moves, as was the case with a transportation bill, a farm bill, and a postal reform bill that cleared the chamber this year.

Republicans charge that Reid’s willingness to change the rules on a 51-vote threshold goes back on a promise he made to follow “the regular order” with regard to rules changes.

Reid and Senate Minority Leader Mitch McConnell (R-Ky.) previously entered into a gentlemen’s agreement whereby Republicans were supposed to allow bills to come to the floor without procedural barriers, and Reid was supposed to allow Republican amendments instead of using a maneuver known as “filling the amendment tree” to block the minority from proposing changes to a bill. But it hasn’t worked out that way.

Now, after blocking Udall’s filibuster overhaul proposal earlier this Congress, Reid supports changing the filibuster rule.

“I think they were right, and I stick by that,” he said.

But not all Democrats want to change the rule.

Reid said on the floor that he has talked with Senate Armed Services Chairman Carl Levin (D-Mich.) about the issue and while Levin agrees it’s been a problem, he still needs some convincing.

Another senior Democrat, Senate Commerce Chairman Jay Rockefeller (W.Va.), said the filibuster is a useful rule that Democrats may not want to alter if they return to the minority.

“If the Republicans take over the Senate I think there is going to be a lot of bills, starting with the repeal of the health care act … cuts of all kinds that we don’t want to have happen and that is where 60 votes can help you,” Rockefeller said.

But Reid said the tool is not being used as originally intended.

“The filibuster was devised — it’s not in the Constitution — it was devised to help legislation get passed,” the Majority Leader said. “That is the reason they changed the rules here to do that. Now it’s being used to stop legislation from passing and we have to change things because this place is becoming inoperative.”

Niels Lesniewski contributed to this report.