Without any constitutional basis, public debate, or even the knowledge of most Americans, passing legislation through Congress had come to effectively require 60 votes in the Senate, or what was often referred to as a supermajority. By the time I was elected president, the filibuster had become so thoroughly integrated into Senate practiceviewed as an essential and time-honored traditionthat nobody much bothered to discuss the possibility of reforming or doing away with it altogether.

A Promised Land by Barack Obama