And it has long since been ruled that where the Constitution calls for a decision and does not specify a supra-majority, the usual rule applies, that it requires only a simple majority.
John / Billybob
Neither has it been tested for any nominees (we can't forget about that, especially with the Bolton issue still looming).
John, I yield to no one in my respect for your constititutional knowledge, but I think you are wrong, for two reasons.
Reason one: The current number of votes needed for the Senate to consent to a nomination is 51. The rule of the majority which you seem to think exists in penumbras and emanations of the treaty clause is in effect.
Reason two: Article I, s.5 constitutionalizes ANY rule the Senate makes about its internal proceedings. If you think Rule XXII has ever been ruled on by a court, I would love the cite. I think its a nonjusticeable question, and I would be very surprised if any Federal court would entertain a challenge.