According to its rules, the Senate cannot vote on a motion if any member wishes to continue debate (i.e. to filibuster). However, as the Senate rules also specify, this rule can be broken if the Senate "invokes cloture."
Invoking cloture requires 60 votes. However, if the issue involves a change in the Senate rules, then invoking cloture requires two-thirds of the Senate, 67 votes if all the senators are present.
Word is that Harry Reid is going to invoke the "nuclear option" and abolish the filibuster for presidential nominees. How can he do this when the Senate rules imply that he needs 67 votes to do that?
If Reid and his fellow Democrats indeed try to end filibusters on presidential nominees, here's the way I suspect they will do it.
First, because of the gravity of the situation (and also because there is the possibility of a tied vote), on the day of the "nuclear option" Reid will ask Joe Biden to execute his constitutional prerogative and be the presiding officer of the Senate. Once the Senate begins debate on a presidential nomination, Biden will recognize a fellow Democrat, most likely Harry Reid. That Democrat will ask that the Senate "move the previous question."
In my class on Congress, as a homework question, I ask my students: "Does the Senate ever use the term 'move the previous question'? What phrase does it use instead?" The answer to the first question is: No, the Senate does not use the phrase 'move the previous question.' That's a phrase that the House uses. It means "to end debate and amendments on the issue at hand and have a vote on the issue." The House rules require only a majority vote to do that.
The Senate, meanwhile, never uses that term. Instead, it uses the term "invoke cloture." It means the same thing as "moving the previous question," but, unlike the House, to execute that concept the Senate requires a super-majority vote.
After a senator such as Reid asks to "move the previous question," I predict a Republican, most likely Mitch McConnell, will quickly rise, and, as Senate rules allow, interrupt by saying "point of order." He will then explain my point above, that the Senate has no concept "to move the previous question."
Joe Biden will then respond, "Yes, it does."
McConnell's only recourse will be "to appeal the chair's decision." This means that he is asking for a vote by all the senators to decide whether Biden is correct or not. Such a vote is decided by a simple majority. Thus, if 50 Democrats are willing to pretend that Joe Biden is correct, that the Senate really has a procedure to "move the previous question," then they can eviscerate the Senate's filibuster rules. They will end the Republicans' filibuster with a 50-vote majority, rather than a 60-vote super-majority as cloture requires.
Some might wonder: How can Joe Biden rule that way when the Senate rules clearly disallow it?
I've seen worse. Consider the example of a friend of mine who was a state senator. His senate had a rule stating that if the governor proposed a bill within the first 10 days of the legislative session, then that bill could receive an immediate vote on the senate floor; it did not have to be reviewed in committee like other bills. The governor once proposed a bill on the twelfth day of the legislation session. Thus, according to the rules, the bill should have been sent to committee. However, the senate president ruled, "No, we are still within the first ten days of the session,"when it clearly was not. My friend asked to appeal the president's ruling. A majority sided with the president, thus declaring that the twelfth day really was within the first 10 days.
I suspect that the U.S. Senate will do something similar. That is, it will rule that the Senate, like the House, can "move the previous question" with a simple-majority vote, even though its rules clearly don't allow such a procedure.
Politico reports that a few Democrats, such as Max Baucus and Carl Levin, are queazy about such a tactic. Thus, maybe I'll be proven wrong. But I suspect that all the Democrats will go along with Reid's plan. Thus, he'll indeed have a majority to execute the nuclear option.