Senate rules since the 1970s (when the filibuster was set at 60) require 66 votes of all senators to effect a rules change. This utilizes the majorities abilit

Senate rules since the 1970s (when the filibuster was set at 60) require 66 votes of all senators to effect a rules change. This utilizes the majorities ability in any parliamentary body to set the precedent or rule on a point of order. hence the 'nuclear' option.