President-elect Donald Trump with wife Melania Trump and Senate Majority Leader Mitch McConnell (R), right, after a Nov. 10 meeting in the Capitol. (Shawn Thew/European Pressphoto Agency)

Last week’s elections placed the filibuster in the crosshairs of Senate Republicans. Many believe that unified Republican control of Congress and the White House come January will encourage Senate Democrats to filibuster the GOP agenda — leading Republicans to curtail the minority’s right to block Senate action.

We can’t know today, of course, if Republicans will “go nuclear,” a controversial parliamentary move that would empower a simple majority of the Senate to limit or eliminate the filibuster altogether. But let’s understand the political dynamics that might give rise to such an explosive move.

Some recent background on the Senate filibuster

When Senate Democrats went nuclear in 2013 to reinterpret the filibuster rule, they targeted the Senate’s Rule 22. The “cloture” rule requires 60 votes to cut off Senate debate (or 67, for motions to debate changes to the rules). Once debate is ended by invoking “cloture,” 30 hours of post-cloture debate must elapse — unless all 100 senators agree to waive it. Only then does the Senate take a simple-majority vote on the measure or motion. After cloture, remaining amendments must be narrowly related to the underlying bill.

In 2013, Democrats changed this for executive and judicial branch nominations (except the Supreme Court). They reduced the number of votes required to break debate to a simple majority — and essentially banned nomination filibusters. Except for those nominations and some measures that are protected by law from filibusters (such as the congressional budget resolution), Senate rules still require 60 votes to cut off debate before the Senate votes.

With an incoming majority of 52 senators (if a Republican wins Louisiana’s runoff election next month), Republicans will typically need eight Democrats to join them to kill a filibuster. That could be hard if Democrats unite to halt Trump’s and Republicans’ efforts, as Republicans have done to Obama.

How likely are Senate Republicans to go nuclear (and end the filibuster)?

To find out, ask the following questions, starting in January.

First, how aggressively and often will Senate Democrats filibuster? One political science theory suggests that threats to go nuclear should tame the minority — encouraging Democrats to filibuster less frequently lest Republicans react by eliminating it. If true, we would expect Democrats to judiciously oppose parts of the GOP agenda. That said, Democrats’ threat to go nuclear failed to tame Republicans in 2013 — persuading Democrats to ban nomination filibusters.

Will Democrats adopt the GOP’s strategy of obstruction, putting the filibuster at risk? We won’t know until we see how the Trump White House and congressional GOP leaders craft the new administration’s agenda. Some Trump priorities (perhaps an infrastructure proposal) might secure Democratic support.

Elections are always around the corner. In 2018, 25 Democratic senators (including the chamber’s two independents) and seven from the GOP face reelection. As shown below, 10 Democrats are running in states that Trump won with an average vote of 55 percent — indistinguishable from Trump support in GOP states. (In contrast, just one Republican, Dean Heller of Nevada, faces voters in a state won by Clinton.)

With an eye on 2018, these Democrats who won in 2012 — sharing a ballot with President Obama — will probably look for opportunities to appeal beyond their Democratic base to Trump voters. If Democrats selectively filibuster or fail to hold their caucus together, Republicans could forgo curtailing the filibuster.


Second, is a majority-rule Senate an unalloyed good for the GOP majority? Certainly, banning the filibuster makes more sense during unified party control of government than when it’s divided. Removing an obstacle to passage makes it more likely that the majority party can secure its priorities.

But some Republican senators also benefit from lax Senate rules — for example, allowing them to take measures hostage with a threat to filibuster. Small majorities tend to be more cohesive. But this slim GOP majority’s hold on the agenda could be tenuous if one or two of the party’s senators uses the rules to advance their own agenda. The filibuster has persisted for over two centuries in part because senators, regardless of party status, benefit from lax parliamentary rules.

Third, will Republicans be able to secure 51 GOP votes to reinterpret Senate rules? I suspect that some of the longer-serving senators, who remember serving in the minority, might be loathe to jettison their future right to filibuster.

Moreover, as Greg Koger reminds us, Republicans themselves might benefit from the filibuster: It allows the GOP to blame the Democrats for blocking parts of the Trump agenda, especially measures GOP senators might oppose. Moreover, requiring 60 votes for cloture would allow Republicans to pursue controversial votes that force electorally cross-pressured Democrats to take costly positions. It’s not clear that Majority Leader Mitch McConnell (R-Ky.) will have the votes to ban the filibuster.

As Steve Smith points out, McConnell could go nuclear incrementally — first ending Supreme Court filibusters if Democrats delay confirmation of Trump’s first nominee and then moving to ban the filibuster of appropriations bills, key legislative vehicles for moving GOP priorities. Republicans could also target filibusters of the motion to call up a bill. In fact, Sen. Harry M. Reid (D-Nev.) probably excluded Supreme Court nominees in 2013 to secure his nuclear majority. McConnell could face similar pressures within his slim conference to more narrowly tailor a filibuster ban should Democrats provoke the GOP to act.

We’ll have to wait and see. 

Of course, Republicans may be more Machiavellian than I’ve credited them. With unified Republican control, partisanship might lead the GOP to punish Democrats with a more extensive filibuster ban, regardless of how Democrats calibrate their use of the filibuster.

When Republicans regained control of the Senate in 2015, they opted to keep the ban on nomination filibusters. Republicans internalized the new parliamentary regime quickly. As Sen. Roy Blunt (R-Mo.) argued, “I think it’s well within the traditions of the Senate for a majority to decide nominations and a supermajority to decide legislation.” Will Republicans still distinguish between nominations and legislation? Democrats’ behavior will shape a GOP decision about going nuclear, as will Republican calculations about their own electoral interests, party goals and the potential burden of carrying legislative water for President Trump.

Killing off filibusters to secure the Trump agenda is not a done deal.