Veteran Senate Democrats agree the chamber’s rules need to be changed to break the current legislative logjam, but some fear detonating a procedural “nuclear” device that could throw the chamber into further gridlock.

There’s a general consensus on the Democratic side that Majority Leader Harry Reid should act to reduce perceived abuse of filibusters on procedural motions and on motions to go to conference, but the Nevada Democrat could face reluctance to a plan that would have him make those changes using a simple majority vote. Their trepidation could increase the incentive for Senate leaders to cut a deal and avoid a toxic standoff in January.

Armed Services Chairman Carl Levin of Michigan and Sen. Mark Pryor of Arkansas this week have been among the most direct in expressing skepticism about that process, which could come through a parliamentary ruling from Vice President Joseph R. Biden Jr., who in theory would declare that the Constitution allows senators to set new rules at the start of the new Congress with a simple majority vote.

In an interview, Levin said that while he agrees on the substance of the changes under consideration, he was “dubious” about the procedural maneuver because it could establish a new precedent that a future majority — Democratic or Republican — could use to establish draconian rules.

“If the majority’s going to write the rules here, it becomes the House of Representatives,” Levin said. House proceedings are often governed by special rules written by that chamber’s Rules Committee, an arm of leadership that is stacked heavily in favor of the majority and almost invariably rejects minority input.

“I’m not a big fan of that,” Pryor said of the “nuclear” or “constitutional” option, adding that he has been “talking to a lot of colleagues about how to make this place run better, but … not a fan of that approach.”

“I believe that before we go down that road we should use the existing rules to force the filibusterers to filibuster. That’s under the existing rules,” said Levin, who faced delays this week in getting the Senate to proceed to the fiscal 2013 defense authorization bill (S 3254) drafted by his committee.

On that point, Levin seemed to echo Senate Republicans — including Armed Services ranking member John McCain, R-Ariz. — who contend that Reid has not kept the Senate in session long enough or made full use of methods available under current rules to wear down senators seeking to filibuster.

“This legislation and how we handle it … can be a model for how this body should do business,” McCain said during a floor exchange with Levin about the defense bill Wednesday. “Take up a piece of legislation, have amendments and debate, and move forward, and if that requires long hours and even occasionally a Friday or even more, then I think our colleagues should be prepared to do that.”

Minority Leader Mitch McConnell, R-Ky., has called the use of extended work hours the “fatigue factor.” For the third consecutive day, McConnell decried the rules change proposal in remarks on the Senate floor Wednesday.

Sarah Binder of George Washington University and the Brookings Institution, who has written extensively about the Senate’s rules, said reservations about a rules fight likely go beyond the mere procedural issues.

“Finding solutions to the fiscal cliff, negotiating tax reform, raising the debt ceiling — these can’t be made any easier by inflaming partisanship at the start of the Congress. I would think that this is giving pause to Democrats: Is this the best timing and approach to pursuing what many seem to judge as relatively incremental changes to Rule 22?” Binder said in an email, referring to the Senate’s rule governing limits on debate.

While the impetus for the changes and the push to use the simple majority procedure started with largely newer senators, it has the backing of some Democrats with lengthy careers. For instance, Maryland Sen. Barbara A. Mikulski said she would back Reid regardless of the method he used to enact the changes. Louisiana Sen. Mary L. Landrieu, who has a track record of deploying rules to her advantage, also signaled a degree of support for the moves next year.

“I am leaning toward those rule changes now, but I’m trying to keep an open mind because I realize it’s a very significant step the Senate would be taking,” Landrieu said. “But, I have to weigh that against the absolute total obstruction” in the Senate now. She cited the record number of cloture motions filed by Reid in recent years.

Landrieu’s position is not unusual. Even Sen. Daniel K. Inouye, D-Hawaii, the most senior senator in the chamber, has said he could support changes to rules governing motions to proceed.

“There is still concern among some of our members, and I understand it,” Majority Whip Richard J. Durbin said. “It is my hope that there is a way to avoid this, to change the rules the traditional way rather than by the constitutional option. But there has been limited indication so far of interest on the Republican side.”

“I am sorry that we have reached this point, but I don’t know any other way to go,” the Illinois Democrat continued.

Because numerous Senate Democrats indicate they are much more comfortable with the changes than the procedure Reid may use to implement them, the majority and minority leaders may well seek a deal to avert the coming procedural crisis, which some top aides expect (or at least, hope) will be the result.

Humberto Sanchez and Megan Scully contributed to this report.