The nuclear option won’t be invoked. Not now, and probably not ever.

The announcement this morning by Senate Majority Leader Harry Reid (Nev.) that a tentative deal had been reached to avert changing the rules governing filibusters makes one thing crystal clear: The chances of the so-called "nuclear option" ever being used is infinitesimally small.

This is a metaphor for the Senate's relationship with the nuclear option.

In the runup to this latest showdown -- triggered by a dispute over seven Cabinet and agency-level appointments made by President Obama and being held up by Senate Republicans -- high-level sources in Reid's world insisted to us that this time the Democratic leader was dead serious about going through with his nuclear option threat.

This time, things would be different. Different than earlier this year when Reid helped to defuse an attempt by younger Democratic senators to change the rules in a broad and meaningful way. Different than 2005 when the "Gang of 14" averted the nuclear option. This time it was for real.

Except not.

The simple truth is this: It's hard to imagine -- given the past decade or so in the Senate -- that the nuclear option will ever be anything more than a sword of Damocles (or maybe we aren't using that phrase properly) hung over the world's greatest deliberative body to force action.

There are a bunch of reasons for this.

First, as we wrote last week when warning Reid to think twice before invoking the nuclear option, politics works like a pendulum -- meaning that things might be swinging your side's way for the moment but they will inevitably swing against you at some point in the future. Changing the rules to allow the majority to rule -- or at least rule more -- means that the rules changes will eventually be used to hamper your side when you are in the minority.  And, no one wants to be on the hook for that sort of political boomerang effect.

Second, the leaders of the two parties in the Senate are, always, institutionalists. You don't rise to the top of your party without a) spending lots of years in the Senate  b) figuring out how to work within the system and c) relishing/treasuring the way the levers of power work. It's impossible -- or virtually impossible -- to imagine someone becoming the Senate majority leader who isn't accurately identified as an institutionalist. (The closest we came in modern memory was Tennessee Sen. Bill Frist , but even he walked back from the nuclear option ledge.)  Institutionalists, by definition, seek to defend and preserve institutions. They have no interest in blowing it up or even really risking that possibility.

Third, the general public has absolutely no interest in or knowledge of filibusters. Given that lack of interest, it doesn't make all that much sense to expend a significant amount of political capital within your own party and poke the other side directly in the eye.

The nuclear option then belongs in the same category as predictions of the end of the world, the Triple Lindy, Dwight Howard getting along with his teammates and Charlie Brown kicking the football. It ain't gonna happen.

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