The Senate is run on precedent as much as it is governed by its official rules. Precedents will sometimes almost directly contradict the actual rules but the precedents actually govern the behavior of the chamber. In fact, using a ruling from the chair upheld by a simple majority, the Senate can set a precedent that a rule means anything, even if it is the total opposite of the clear intent of what the rule states. What this means is that any potential reform to the Senate’s rules wouldn’t just end with adoption of new official rules. The actual impact of these rules can be radically shaped by what precedents are set when interpreting the enforcement of these rules.

A critical example of the importance of precedent is that Senate rules require 60 votes for cloture, but it was a precedent set in 1975 that prevents post-cloture filibusters by amendments. Without this precedent, the cloture vote requirement would be made a meaningless threshold, since a handful of senators could still stop a bill from getting a vote by introducing an endless stream of amendments.

With new rules comes the potential to set new precedents about these rules.

Among the potential rule changes being pushed that could end up the most important depending on what precedents are set about them could be rules meant to force a return to the “talking filibuster” as explained by Sen Tom Udall (D-NM) to Brian Beutler:

As things currently stand, the onus is on the majority to put together 60 votes to break a filibuster. Until that happens, it’s a “filibuster,” but it’s little more than a series of quorum calls, votes on procedural motions, and floor speeches. The people who oppose the underlying issue don’t have to do much of anything if they don’t want to.

Here’s how they propose to change that. Under this plan, if 41 or more senators voted against the cloture motion to end debate, “then you would go into a period of extended debate, and dilatory motions would not be allowed,” Udall explained.

As long as a member is on hand to keep talking, that period of debate continues. But if they lapse, it’s over — cloture is invoked and, eventually, the issue gets an up-or-down majority vote.

This would still likely leave important room for interpretation about what qualifies as “lapsed” and “dilatory” in this period of extended debate. Depending on how new precedents are set about this rule change the impact could be minor or huge.

If the Senate interpreted the rule to still allow for easy delay tactics, say the ability to introduce a germane but extremely long amendment that the clerk can be forced to read, forcing a “talking filibuster” could be almost as easy as the currently “painless” filibuster. The result would be no real change.

On the other hand, precedent could be set to make it extremely hard to sustain a continuous talking filibuster. It could be made so hard that it would almost guarantee that over the course of several days the minority would eventually allow debate to lapse and cloture would be invoked automatically. For example, a strict enforcement of the two speech rule (PDF) declaring any action a speech (eliminating delay by quorum calls), giving the chair authority to declare all amendments and motions “dilatory”, and/or a definition of “lapse” that means as little as 5 seconds without an opposing speaker on the floor could make endless delay through a talking filibuster practically impossible.

The impact of such an interpretation would be huge. It would turn the filibuster from a 60-vote threshold for any bill to at best an exhausting week-long delay for the minority that will almost always end in the bill eventually getting an up or down vote. Making the filibuster extremely exhausting and very easy to accidentally lapse could result in the minority losing all desire to attempt filibusters, thereby turning the chamber effectively back into the majority body the framers intended.

Rules are important but it is precedent that reigns superior

I will be paying very close attention any Senate rules reform at the beginning of next Congress, but I will be paying at least as much attention when the new rules are first put to the test when new precedents likely will be set. This is really where the rubber meets the road and also will likely end up being decided by a simple majority vote.

After all, the early Senate rules were never written with the intent of allowing for a filibuster. The practice evolved into what it is thanks in large part to precedents that set very lax rules about what qualified as debate, speeches, and holding the floor, making a filibuster very easy. Part of what makes the current filibuster so “painless” is that the Senate has a precedent that quorum calls are not speech, giving Senators a very easy way to force endless delays without using up one of their two speeches. New precedents, however, could just as easily make filibusters functionally impractical.