Majority leader Harry Reid (D-Nevada) on the Senate floor before detonating the nuclear option. (Screen shot from C-Span2, November 21, 2013.)

What broader lessons about the Senate and its capacity for change can we draw from Democrats’ detonation of the nuclear option this past week?  In what amounted to more of a surgical strike at the Senate’s Rule 22 than blowing up the institution, Democrats reduced the number of votes required to end debate on nominations to just a majority — rather that 3/5ths– of the chamber.

Two questions deserve consideration: Why did the Senate go nuclear now, and what will be the consequences for future majorities eager to further curtail the filibuster?

So, first, why now?  One prominent view of the Senate is offered by Greg Koger here on the Monkey Cage.  He notes that “Thursday’s events illustrated that a simple majority of senators can restrict filibustering whenever they choose.”  As Koger suggests, the majority has always had the capacity to set precedents by majority vote, thereby  circumventing the formal rules of the Senate that require 67 votes to break a filibuster of a rule change. And as Wawro and Schickler argue here, the capacity to go nuclear tames minorities from abusing their rights of extended debate. Thursday’s turn of events begs the question of why the threat was detonated now and why it failed to tame the GOP.  In contrast to these accounts of the Senate, Steve Smith, Tony Madonna and I have argued that the capacity to go nuclear has generally been *technically* feasible but not always *politically* feasible.

So what made deploying the nuke politically feasible this time? The relative costs and benefits of deploying the nuke shifted measurably for the majority.  First, fear of minority retaliation (which would have increased the majority’s costs of going nuclear) no longer weighed heavily on the majority’s calculations. As Majority Leader Harry Reid put it, “What could they do more to slow down the country? What could they do more than what they’ve already done to stop the Senate from legislating?” Second, Democrats’ perceptions of GOP overreach (which increased the partisan benefits of banning filibusters of nominees) finally persuaded more senior, reluctant Democrats to support Reid’s nuclear gambit.  Perceptions of GOP overreach likely also made it easier for Democrats to shift the blame for going nuclear to the GOP, thereby making Reid’s nuclear gambit more politically feasibility.  (That strategy worked, save for editorials like the Washington Post’s that decried the Democrats’ heavy-handed ways.)  In short, even most long-serving Democrats (including Reid) likely calculated that there was a lot to win and little to lose by striking down nomination filibusters with a nuclear strike.

If that shift in costs and benefits was plainly evident to Democrats, why didn’t the threat tame the GOP?  One possibility is that Minority leader Mitch McConnell badly miscalculated by underestimating how many votes Reid held for going nuclear.  Given several Democrats’ long-standing reluctance to circumvent the chamber’s formal rules to reform the cloture rule, that would have been a reasonable mistake on McConnell’s part.  (That said, one of the more reluctant senators, Barbara Boxer, noted as early as the beginning of November that she had become more open to going nuclear.)  Still, Jonathan Bernstein offers an alternative explanation for why the GOP failed to drop its judicial blockade, arguing that the more pragmatic GOP senators had tired of being targeted by conservatives for providing pivotal votes for cloture.  If true, then Republican senators gave up the filibuster to save themselves.  Given that senators’ defense of the filibuster has historically been driven by their political interests rather than by institutional principle, we shouldn’t be surprised to see many Republicans make that tradeoff.

Second, what are the consequences of this past week’s nuclear move for the future of the filibuster? Historically, major Senate reform of chamber debate rules has been extraordinarily rare, even under conditions of remarkably decreasing returns for the majority of senators.  Only rarely have the costs of living under the Senate’s byzantine rules proved high enough to provoke enough senators to pursue reform that abides by the Senate’s formal rules (that requires a supermajority to kill a filibuster of reform).  Assuming the nuclear move sticks, Democrats have shown that a majority can bear the political costs of reducing the cloture threshold by creating a new precedent by majority vote rather than by formally amending the Senate’s cloture rule by supermajority.

To be sure, Koger and other have argued that majorities have always had this capacity. But Democrats have now demonstrated that a sufficiently frustrated majority can sustain the political costs of pushing the nuclear button on the most critical element of Senate rules.  Majorities have detonated several previous mini-nukes, but none have tackled the true target of ardent Senate reformers since the middle of the 19th century– the number of votes required to kill a filibuster and to bring the Senate to a vote. Whereas the Senate’s past institutional path dependence has repeatedly put major reform out of reach, the Senate’s post-nuclear path dependence makes future reform far more easy for a cohesive and frustrated majority.  I doubt the Senate will ever “become the House,” not least because key constitutional differences between the chambers (staggered elections, state representation, six-year terms and so on) cannot be waived by majority vote.  But my hunch is that Democrats’ nuclear precedent this week reshaped the path of future reform.   To be sure, majorities must be willing to pay the costs of such reform, but those costs fell sharply and significantly this past week in the Senate.