“ I wouldn’t be surprised if they pull the trigger on Tuesday,” says Sen. John Cornyn, the second-ranking Republican in the Senate. “Reid has gone so far out on a limb.”

By “pulling the trigger,” Cornyn means that Majority Leader Harry Reid will go through with threats to eliminate the minority’s right to filibuster, at least in the case of executive branch nominations. Reid has been all over the map on the question, in the past pledging never to do such a thing and now threatening to do it within a matter of hours. This time, Republicans seem to believe him.

In what appears to be a last-ditch effort to avoid a crisis, all 100 senators will hold a special meeting Monday night. But Cornyn doesn’t hold out much hope. “Sen. Reid feels like he has to check that box,” Cornyn says, indicating that he believes Reid is holding the meeting more for show and to be able to claim that he did everything he could to avoid pulling the trigger — before pulling the trigger.

It’s not the first time the parties have reached an impasse over blocked nominations. In 2005, after minority Democrats filibustered an entire slate of Bush judicial nominees, majority Republicans threatened to eliminate the filibuster for judicial nominations. With a showdown approaching, senators formed the so-called “Gang of 14″ and negotiated a settlement. Some nominees were confirmed, some were killed, and the parties promised not to filibuster judicial nominees in the future except in “extraordinary circumstances.” (Those circumstances were left undefined.)

“Everybody got to the edge of the precipice and looked into the abyss and pulled back,” Cornyn recalls. “They realized that what goes around, comes around. But I have a different feel of it this time. I have a feeling that Reid has gone so far out on a limb. He’s promised not to do this, but he has so much pressure from some of these relatively new people in his caucus. There are not enough of the old hands who will say, ‘You have to realize, this could come around and bite us.’”

Cornyn specifically mentioned Democratic Sens. Jeff Merkley, Mark Udall, and Sheldon Whitehouse, all of whom are pushing hard for filibuster “reform.” Merkley and Udall came to the Senate in 2009, and Whitehouse in 2007, so all have served only with a Democratic majority. “They have bought into this narrative that it’s all the Republicans’ fault,” says Cornyn.

Of course, back in 2005, Cornyn, who came to the Senate in 2002, had never served in the minority and favored limiting the filibuster. “I was one of those who argued when the Democrats filibustered judges for the first time that the Senate could do the nuclear option,” Cornyn says. “I felt that the Senate rules could not trump the Constitution. But the Gang of 14 was essentially a negotiated settlement which established a new precedent.”

But now there’s no negotiation, although there might conceivably be some progress Monday night. But the fact is that Republicans blame Reid for running the Senate in a particularly abusive way, twisting the Senate’s rules to limit the minority’s ability to offer amendments and setting off cloture fights on even relatively routine matters. Democrats, of course, accuse Republicans of bringing the Senate to a halt.

Cornyn realizes the majority has the power to make the change, if it wants. “No one denies that as a practical matter it’s possible to do so,” he says. “What people are reluctant to do is start down a slippery slope where you do this on executive nominations, and then it goes to judicial nominations, and then to regular legislation.” If that were to happen, the filibuster, which in the past has been used to stop both good legislation and bad, would be gone.

And that would probably bring on a wave of Republican reprisals. They don’t call it the “nuclear option” for nothing — Reid’s action would likely set off a nuclear winter inside the Senate that might last for a very long time. It’s the kind of thing that, in the past, called for cooler heads to find a solution. This time, however, that might not happen. “It doesn’t feel like that right now,” says Cornyn. “It feels like Reid has escalated this thing to a point where it’s hard to see him going backward.”