President Joe Biden's agenda has stalled on Capitol Hill halfway through his first 100 days in office. Biden's supporters fear that if Democrats in Congress don't act soon, they will have squandered their best opportunity to pass such policy priorities as a climate action bill, election legislation, and immigration reform. Supporters are especially frustrated with Senate Democrats for allowing their chamber's Republicans to filibuster bills passed by the Democratic-controlled House.
The Senate, unlike the House, permits a minority of its members to block bills supported by a majority. Specifically, Rule 22 requires three-fifths of the Senate (60 senators) to vote to end a filibuster by invoking cloture on a bill. To end a filibuster of a proposal to change the Senate's rules, Rule 22 says you need even more votes: two thirds of the senators present and voting. (Normally that's 67 people.) In effect, Republicans can block a final vote on Democratic priorities because the Senate's rules require more votes to end debate on a bill than they do to approve it.
A growing number of Biden's supporters want Senate Democrats to abolish the filibuster through another route: the so-called nuclear option. This is a procedural maneuver senators can use to ignore, circumvent, or otherwise change the Senate's standing rules by a simple majority vote in direct violation of those rules. Basically, they create a new precedent that is inconsistent with Rule 22 but nevertheless supersedes it.
Yet just because Senate Democrats can use the nuclear option to eliminate the filibuster does not guarantee they will do so. Democrats must first secure the votes required to go nuclear before using the maneuver to jump-start Biden's stalled agenda. And their ability to do that is contingent on the actions of individual Democrats and Republicans.
Before 2013, Senate majorities used the nuclear option only rarely. In November of that year, Democrats employed it to abolish the filibuster for all presidential nominations other than Supreme Court justices. In 2017, Republicans used it to abolish the filibuster for Supreme Court nominations. They deployed it again in 2019 to shorten the amount of debate permitted under the rules after the Senate has invoked cloture on a nominee but before a final confirmation vote.
Notwithstanding this increased willingness to use the maneuver, Democrats may not be able to go nuclear in the weeks ahead. Both Sens. Joe Manchin (D–W. Va.) and Kyrsten Sinema (D–Ariz.) have both publicly opposed doing away with the filibuster at all. And several other Democrats who might be willing to end the filibuster have not yet publicly committed to doing so via the nuclear option.
These holdouts may believe they benefit from the filibuster. Or they may think that the costs of eliminating the filibuster are greater than those associated with maintaining the Senate's status quo. Regardless of the reason, Democrats need every single Democratic senator, plus Vice President Kamala Harris' tie-breaking vote, if they are to use the nuclear option successfully in the evenly divided Senate.
Meanwhile, Republicans could retaliate if Democrats abolish the filibuster. Senate Minority Leader Mitch McConnell (R–Ky.) has already threatened that if the Democrats use the nuclear option and the Republicans then take the majority, he could use the maneuver in the future to pass legislative priorities opposed by Democrats. If such threats convince rank-and-file Democrats that it would be harder to achieve their individual goals in a post-nuclear Senate, that may be sufficient to deter Democrats from supporting the nuclear option.
That said, the GOP's past behavior may undermine the credibility of McConnell's threat: Republicans did not retaliate when Democrats used the nuclear option in 2013, and they used it themselves in 2017 and 2019. The specific nature of McConnell's threat may also weaken its deterrent effect: By signaling that a Republican majority would be likely to go nuclear in the future, it could lead Democrats to discount the utility of adhering to the rules in the present.
Notably, McConnell did not threaten immediate retaliation that would impact rank-and-file Democrats if they support going nuclear, beyond vaguely suggesting that doing so could theoretically cost Republican cooperation moving forward. Republicans made similar unspecified threats in 2013, and they were not successful in stopping Democrats from using the nuclear option.
That said, Democrats' expectation of retaliation may temper some senators' willingness to support the nuclear option because the perceived costs of doing so could exceed the benefits they hope to gain. The filibuster's fate is contingent on Democratic senators' cost-benefit calculations—and on Republicans' ability to nudge those calculations in the direction they prefer.