Senate Majority Leader Harry Reid (D-NV) listens during a news conference on Capitol Hill on June 21, 2012 in Washington, DC. The Democratic leadership addressed issues including the resignation of Commerce Secretary John Bryson and the expected Supreme Court ruling on the Affordable Care Act. Photo: Brendan Hoffman/Getty Images

If you’ve been cowering in your underground survivalist fallout shelter for fear of Senate Democrats unleashing the “nuclear option” you have been hearing about, you can come out now. Senate Democrats have decided they’re not going to use it. (Also, it was a metaphorical nuclear option rather than a literal one, so you probably didn’t need to be hoarding food and water.) Unlike the last time Democrats threatened to change the Senate rules, and backed down without winning anything, this time they won something important: They broke Senate Republicans’ ability to hold presidential appointments hostage. It’s a total victory for the Democrats.

The cause of the crisis is that Senate Republicans have been filibustering key nominations for the executive branch. Traditionally, the Senate lets the president pick his own team, unless he picks somebody unusually terrible, like a serious drunk or a crook. Republicans have been blocking completely normal Obama nominees to the National Labor Relations Board and the Consumer Financial Protection Agency, not because they object to those nominees, but because they don’t want those agencies to function at all. It’s a completely new and dangerous tactic.

Democrats had proposed to change the Senate’s rules to prevent filibusters on executive branch nominations (but not to ban filibusters of legislation or judicial nominees). They’ve won.

Mitch McConnell, architect of the Republican strategy, had reportedly insisted that Democrats agree to foreswear any future rule change in exchange for this, but doing so would have given Democrats no recourse if he started blocking other, future nominees. So the deal is that Republicans lift their filibuster, and Democrats don’t change the rules right now.

Republicans got one face-saving concession: Democrats have to pick new names for the NLRB. This became an issue because Obama tried to execute an end-run around Congress by appointing them to their positions when Congress was functionally, though not technically, in recess, and was struck down by the Republican-controlled D.C. circuit court. McConnell had hilariously argued that the “illegal” nominees were the cause of the whole standoff, which was a bit like describing the Battle of Gettysburg as the cause of the Civil War. So now Obama has to pick new NLRB nominees, but the terms of the deal apparently allow him to pick basically anybody, which seems to be the opportunity for the president to finally doff his mask of moderation and go ahead and appoint Saul Alinsky, who has been secretly alive and living in Obama’s underground Chicago lair all along. Republicans have already agreed to let him through!

The deal was brokered by John McCain, who undercut McConnell and is fully emerging, yet again, as his old centrist self. Exactly what happened to flip the switch in McCain’s brain from “Obama Hater” back to “McConnell Hater,” it is hard to say. Whatever it is, the old-new McCain is back again, which seems to be a significant development, given Obama’s inability to find any Republicans who aren’t terrified of working with him.

Also notable is that the threat of the nuclear option has once again succeeded. Republicans threatened to change the Senate’s rules in 2005 to stop Democrats from filibustering their judges, and it succeeded — Democrats agreed to let pretty much any judges through with a majority vote. Once again the majority party forced the minority into a total capitulation. There is a lesson here, and it’s not that the Senate is a wonderfully congenial place whose rules must not be touched.