In fact, as I've said before, academic experts on the Senate are as far as I know unanimous that a majority who really want to change the rules could do so at any time. The only real constraints are political, not legal.
But don't take my word for it. After I posted about this recently, I exchanged email with Greg Koger, author of Filibustering, and one of the handful of real academic experts on Senate rules. What follows is Greg's description of how the Senate could, at any time, change its rules with respect to the filibuster (I edited out email-specific references, e.g. "as you know"; otherwise, it's all him). I'll come back at the end with couple of quick comments. Take it away, Greg:
First the "how":
Long story short, all the majoritarian strategies I know of take the form of raising a pending point of order and a 2nd point of order arises, that 2nd point will come to a vote immediately. This is the majority's ace in the hole: if the minority is filibustering their effort to get a vote on a ruling, then a member of the pro-reform majority can raise a 2nd point of order that debate on the 1st question has gone on too long, or is not allowed. The members of the House did this in 1811., obtaining a ruling from the presiding officer, and then either affirming or rejecting that ruling to achieve the desired effect. Sarah Binder and Steve Smith stress that it may be "difficult" for a majority to get a direct vote. My reply is that the rules of the Senate provide that if there is a
Now the "what":
First, I should stress that there are lots of possible strategies. In Riker's terminology, this is a "heresthetic" task so the only limit is the creativity of pro-reform senators. When I list options, then, they are suggestions that have been made previously, or strategies I have come up with, but no list is exhaustive. That having been said, here are some options:
1) The Previous Question. Step 1: a senator moves the previous question. Of course, this will lead to a point of order that the Senate does not have a PQ motion. Then a direct vote on whether the Senate has a PQ motion or not! It's like changing the rules, but without the 2/3 cloture threshold.
2) The Yeas & Nays. I have made the case that filibustering is neither expressly mandated by the Constitution, nor is unanimous consent agreement to hold the votes.a Constitutional imperative. On reflection, though, I think there is a valid Constitutional argument to be made. Article 1, Section 5 states that "...the Yeas and Nays of the Members of either House on any question shall, at the Desire of one fifth of those Present, be entered on the Journal." The current practice of the Senate nullifies this provision, as senators often request and receive roll call votes that never occur because some senator objects to a
When there is a measure on the Senate floor (say, a START treaty) the yeas & nays have been ordered, and a reasonable amount of time (I won't call it "debate") has elapsed, any senator can raise a point of order that the constitutional right to a vote is being abrogated by the practice of the Senate.
The strength of this approach is its clear foundation in the Constitution; its weakness is figuring out how to allow a reasonable amount of debate between calling for the yeas & nays and actually holding the vote. The U.S. House had a similar problem in the 19th century with the previous question motion, since the PQ had to be moved by the MC who brought up a measure before he yield the floor, so there was a monologue and then a vote (or obstruction by other means).
3) Convert the motion to suspend the rules. Senate rule 5 allows motions to suspend the rules, and these motions can include all the detail of a special rule in the House--calling up a bill, laying out the terms of debate and amendment, and then a time certain for a final passage vote. Unlike the comparable, Senate rule 5 does NOT specify a threshold for suspending the rules, so the default interpretation would normally be that a simple majority is required. BUT, in 1915 and 1916 the Senate enacted precedents that a 2/3 majority is required to suspend the rules; this is my favorite example of how much discretion legislators have to "reinterpret" rules when they want to.
So, if senators want to eliminate obstruction, this would be my recommended option, since the reform is perfectly defensible within the context of Senate rules. That is, the reformers would be making changes so that the rules are MORE logical, more consistent. There are two steps:
a) set a precedent that the motion to suspend the rules is nondebatable (that is, it cannot be filibustered)
b) reverse the 1915 precedent so that a simple majority is required to suspend the rules. Voila! The majority can cut off a filibuster whenever it wants.
Note that the majority can stop at step a). That would at least decrease the importance of holds by setting up a swift process for challenging a filibuster by a 2/3 majority.
4) Convert Rule 22. This option is...unpretentious. A senator files a cloture petition on a bill, nomination, or treaty. Wait 2 days. Vote at noon. So far, so normal. But if the number of votes for cloture is over 50 and under 60, then when the presiding officer states that the cloture attempt has failed, a reformer raises a point of order that a simple majority is required to invoke cloture. This is a bold-faced coup, since Rule 22 clearly says "three-fifths of the whole Senate." BUT, the advantage of this approach is that there is an easy 2nd-degree point of order to raise if debate on the 1st point of order drags on...once cloture is invoked, there is no debate on appeals to points of order, so if there is debate on the 1st point of order, a reformer can point out that, since cloture has been invoked (right?!) there is no debate on the 1st point of order. This brings the effort to a swift, critical vote.
There are other options, but these are ones that first come to mind. In particular, I should note that there are some incremental reforms that can be adopted by precedent, e.g. bundling nominations. And, it is worth noting that senators who are reluctant to use confrontational methods would still be wise to retain them as an option, if only to motivate the minority to agree to reasonable, modest reforms for fear that the majority will unilaterally impose more drastic changes.
Two quick comments. First, I disagree with Greg's position on the proper Constitutional status of filibusters. As I read it, I think that the "entered in the Journal" clause only means that if a vote is taken that the Yeas and Nays must be, when requested by enough Senators, recorded. As to whether a vote is taken at all, "Each House may determine the Rules of its Proceedings" is what matters. Under Greg's interpretation, couldn't twenty Senators (or one fifth of the House) force a vote on something that was stuck in committee? However, whether I'm right or Greg's right about this is irrelevant to what the Senate could rule. I certainly don't think the courts would step in to prevent such a ruling, regardless of the strength of its Constitutional claim.
Second, if you skipped the rest, read the last paragraph, which points out that the majority can use the threat of unilaterally changing the rules to negotiate something more reasonable. This suggests to me that it may be a mistake for Udall and other reformers to put all their eggs in the Opening Day basket: it'll be rough enough to change rules in mid-session without having a whole bunch of reformer Senator quotes about how it's the only chance. Especially since it isn't true.
Also, note that Harry Reid could, if he wanted to and had 60 votes, bundle up all the remaining nominations and push them through together, which would dramatically reduce the floor time needed if Republicans delayed as much as possible.