The debate over the “nuclear” option has gone nuclear, literally, even as it appears the odds of a Senate war over filibusters are fizzling.

Sen. Lamar Alexander, R-Tenn., says he doesn’t think Senate Majority Leader Harry Reid will do away with filibustering of nominations this summer, even as he and other Republicans are warning of repercussions — including to Reid’s own long-standing effort to keep Yucca Mountain from being used as a nuclear waste site.

Alexander may be right, at least for now. Sen. Christopher S. Murphy, D-Conn., said this week he doesn’t believe that Democrats have 51 votes to make the procedural move with a simple majority, known as the nuclear option.

“Not right now,” Murphy said. “There are still a handful of Democrats who are reluctant.”

Murphy noted that the nine freshman Democrats have publicly supported a Democratic proposal to curb filibusters drafted by Sens. Jeff Merkley of Oregon and Tom Udall of New Mexico.

Hours after speaking on the floor, Alexander insisted that he thought Reid wouldn’t ultimately make a move.

“I expect him to keep his word,” Alexander said of the Nevada Democrat. “I expect him to have read his own book. I expect him to not want Yucca Mountain to be — completed, and if he believes all those things, he’ll forget these threats.”

Yucca Mountain is the proposed Nevada nuclear waste repository that Reid has long crusaded against, unafraid to leverage the clout of the majority leader’s office time and again to kill the project.

Asked at a news conference about Alexander’s comments by a reporter for a Las Vegas newspaper, Reid declined to take the bait.

“The Republicans have been marching to the floor for a week or two talking about me, and I’m not gonna respond to ’em,” Reid said.

Sen. Dean Heller, R-Nev., who also opposes Yucca Mountain, jumped in with his own statement.

“The Nevada delegation needs every arrow in our quiver to keep the nation’s nuclear waste out of our state. Nevada shouldn’t be the fallout from the battle of the nuclear option,” Heller quipped.

Alexander, Minority Leader Mitch McConnell of Kentucky and other Republicans say they want Reid to reaffirm that he will not use such a procedural device, but such a statement might reduce Reid’s leverage on nominees this summer.

Alexander’s argument is that there would be no way to stop a narrowly tailored procedural change engineered by Senate Democrats to make it easier to confirm President Barack Obama’s judicial and executive branch nominees from expanding to all legislative business in a future Congress, particularly under GOP control.

“If the Democrats change the rules so that they can do anything they want with 51 votes, that will be the way the Senate will operate when the Republicans are in charge, and one of the first things we’ll do is complete Yucca Mountain, and then one of the second things we’ll do is to repeal the death tax and one of the next things we’ll do is to drill in ANWR,” Alexander said. “So, Democrats need to think about that if they think this is an improvement.”

For his part, Murphy has aggressively backed rules changes since a firearms background check proposal fell when it failed to get the customary 60 votes earlier this year.

“I’m a revolutionary on this. I think we should go to majority rule, but I understand that it has to come one step at a time” Murphy said. “Gina McCarthy was a Republican appointee in my state. I can vouch for the fact that she is not going to be a shill for the Obama administration. If they are going to hold her up and [Richard] Cordray at least with respect to nominations.”

McCarthy is Obama’s nominee to head the EPA and Cordray is the current head of the Consumer Financial Protection Bureau, serving with a recess appointment. Cordray’s been nominated to the post, but Republicans have objected to anyone holding the job until Congress enacts changes to the bureau’s structure.

Republicans are also opposing nominees to the National Labor Relations Board that are the subject of legally disputed recess appointments.

Democrats and Republicans also differ on whether judicial nominees have been moving through the confirmation process swiftly enough, repeatedly citing different statistics comparing the current state of nominations to those under President George W. Bush.

Alexander said it would be “correct” to characterize the Republican position as having changed from the one espoused by then-Majority Leader Bill Frist.

Frist, a fellow Tennessee Republican, seemed to be prepared to eliminate filibusters of Bush’s judicial nominees to get around what he viewed as Democratic obstruction, until the bipartisan “gang of 14” senators emerged with a compromise that prevented him from having the votes needed to move forward.

Judiciary Chairman Patrick J. Leahy, D-Vt., announced Monday that he planned to hold the first nomination hearing on one of that slate of nominees after the Fourth of July break, meaning a floor fight could come in July or after the August recess. Leahy says the caseload arguments are preposterous since Republicans haven’t had similar concerns about other circuits.

“I do not recall seeing any bills from Senate Republicans to eliminate the Oklahoma and Iowa judgeships,” Leahy said Monday.

Humberto Sanchez contributed to this report.