Quote Originally Posted by Eric P View Post
It's a rule not mandated in the Constitution and can be revoked at anytime by the majority.
Yep. The specific instances in which the US Constitution requires a 2/3 vote in the Senate are limited to: 1) convict in an impeachment; 2) expel a member; 3) ratify a treaty; 4) override a veto; 5) pass a constitutional amendment; 6) restore rebel's rights to serve (14th Amdt; 7) approve a presidential removal (25th Amdt). The last 4 also require 2/3 vote in the House.