Part I: Why can't they just change the rules?
Part II: The Rules vs. the Constitution
When we last left off in this intermittent series, we'd discussed: 1) what's standing in the way of just changing Senate rules if they want to, and; 2) the apparent paradox posed by the Constitution's grant of power to each house of Congress to set its own procedural rules by majority vote, and the Senate's assumption that it was a "continuing body" and that its rules -- including the rule requiring a 2/3 vote to end a filibuster of a proposed rules change -- also remained in effect from one Congress to the next.
Since then, many of you have researched or figured out on your own how that paradox might be addressed, and that has landed you on or near what's become known as the "constitutional option." Perhaps you've seen it discussed by Ezra Klein recently, or read one of several diaries at Daily Kos that have either discussed the very same procedure, or proposed variants of it, or even invented something similar from whole cloth, apparently even without any previous knowledge of the Senate's history with the maneuver.
But the very basic run-down is this: The Senate has, under Article I, Section 5, clause 2 of the Constitution, the right to determine its own procedural rules by majority vote. At the same time, it has adopted as one of its rules (Rule V) an explicit statement of the "continuing body" doctrine that says that because at least 2/3 of the Senate is always sitting in and sworn to office (since only 1/3 stand for election every two years), the Senate always has a continuous and uninterrupted quorum available to do business (a simple majority constitutes a quorum) and therefore continues to operate at all times, and brings its existing rules along for the ride.
Since one of those continuing rules (Rule XXII) is the one that requires a 2/3 vote to invoke cloture on a rules change, it is assumed that there exists a tension between the majority vote right conferred by the Constitution and the 2/3 requirement. That tension has in the past been addressed by the recognition of a sort of magical window said to exist at the beginning of a new Congress, during which it is possible to operate outside of the restrictions of Rule XXII -- and indeed all existing Senate rules -- and have the Senate adopt its rules anew or amend them by a simple majority vote.
Here's the theory: The Constitution's grant to each house of Congress of the right to adopt its own rules of procedure by majority vote can mean nothing if it can be trumped by the actions of a previous Senate, and rewritten to require a supermajority. And you simply can't permit the Constitution's clear delegation of a specific power to be swept aside forever, particularly by the decision of a relative handful of Senators, most of whom are now long dead. In order for Article I, Section 5, clause 2 to have any meaning, there simply has to be an opportunity for a sitting Senate to decide for itself -- without interference from previous and/or dead Senates -- what its rules of procedure will be going forward. This is the "principle against binding," that is, the legal principle which holds that a legislature cannot by its previous action constrain its own subsequent action, and certainly no previous iteration of the legislature may prevent specific action by future iterations of that legislature. In other words, the dead Senates of the past can't force the live, current Senate to live by the old rules unless the current Senate agrees to do so.
But because of this "continuing body" theory now (but not always) embodied in Rule V, the Senate has really never actually made a practice of explicitly agreeing to continue under the old rules. They just... did. Because. Because that's the way it's always been done. (And you know right away you're in trouble when you find yourself saying that.)
So if the principle against binding makes sense to you, and the continuing body doctrine makes sense to you, and you know that the Senate has never really bothered to explicitly accept the continuance of the rules and that's never appeared to be a problem before, then how do you reconcile these two things?
Well, you have to construct another theory to explain it all. And here it is: each "new" Senate (if the continuing body doctrine makes it possible to even contemplate such a thing) does in fact make some indication of its acquiescence to the continuation of the old rules. It's just that the "action" is a negative one. Upon first convening, if the Senate as a body gives no indication that it doesn't want to continue under the old rules, and indeed proceeds to conduct routine business as though the old rules continued in effect, the Senate by beginning to conduct that routine business is deemed (and remember: GOP sez deeming bad!) to have agreed by unanimous consent to the continuance of those old rules. That would explain how the lack of any explicit action on the rules in years past could survive the principle against binding. By not raising any objection to the continuance of the old rules, the "new" Senate has in effect agreed to their continuance, and has therefore not been bound at all by the "old" Senate.
But if instead of silence, the convening of a "new" Senate is instead met with the objection of one or more Senators to the continuance of the old rules, that "magical" window is opened up, and the rules are in play.
The question is, under what ground rules are the old Senate rules in play? It can't be the Senate rules themselves, since the whole point of the objection is to prevent their being agreed to as the "operating system," as it were.
The answer arrived at in 1917, during the debate that led to the adoption of the original cloture rule, was posited by Sen. Thomas Walsh (D-MT): that until Senate rules are affirmatively adopted or acquiesced to, the Senate convenes and operates under general parliamentary law, under which new rules may be adopted by a simple majority. And this also happens, not coincidentally, to mesh perfectly with the assumption the canons of construction lead us to when we interpret the lack of an explicit supermajority requirement in Article I, Section 5, clause 2.
In fact, that made so much sense in 1917 as a solution to the apparent Rules vs. the Constitution paradox that it's remained the preferred solution to the present day, though it's not been frequently invoked.
Next, we'll review how and when it has been invoked with regard to cloture and cloture reform.