In response to my post below, David Repass comments:

Jonathan Adler asks me (rhetorically) "Where was Prof. RePass when 'phantom filibusters' were used against President Bush's judicial nominees?" My answer is: in the same place as I am now. It's just that I didn't try to get my view published in The New York Times back then, but I did teach it to students in my courses. My view then (as now) is that the majority leader should let filibusters -- real filibusters -- take place. If the minority is so intensely concerned about something that they are willing to mount a filibuster, then let them take the Senate floor and state their case. If Democrats were so concerned about certain Bush judicial appointments, then Bill Frist should have let them risk public opprobrium for holding up Senate business with a filibuster.

It is clearly unconstitutional for any majority leader to require 60 senators to support every controversial piece of legislation before it can even be debated. This fundamentally changes the Constitution and is not simply a procedural matter.

For more on filibusters, see these items by Sandy Levinson and Jean Edward Smith.