Some argue that any supermajority requirement is unconstitutional, other than those specified in the Constitution itself. I find much in this theory to agree with--and I think we should treat all the rules that would limit the ability of a majority to rule with skepticism. I think that this theory is one that we ought to examine more fully, and that is the idea that the Constitution of the United States sets up certain specified instances in which a supermajority is needed to pass the bill, and in all other cases it is silent. In fact, the Constitution provides that the President of the Senate, the Vice President of the United States, can only vote to break a tie vote--by implication, meaning that the Senate should pass legislation by a majority vote, except in those instances in which the Constitution specifically says that we need a supermajority.
More Harkin.