Ramesh raises a point that has been addressed by a number of readers as well. I could of course be wrong about the validity of filibusters — I hope not, but I have (no matter how you slice it) been wrong at one point or another. But I don’t think this much should be debatable: Article II, Section 2, Clause 2 does not draw distinctions among the high government officials the president is empowered to appoint. As a matter of constitutional law, if the filibuster is impermissible for any, it should be impermissible for all.
Obviously, the political considerations are different — e.g., lifetime judicial appointments raise different concerns than limited-term executive posts. Also, the fact that no one has tried to filibuster an executive branch official may be a good reason for steering clear of that potential problem in the context of dealing with the judges. But, as a narrow matter of law, I don’t think it would be any more appropriate to filibuster John Bolton than it would to filibuster Judge Pryor.