when did the senate changed to 60 votes
Nuclear option Beginning with a rules change in 1806, the Senate has traditionally not restricted the total time allowed for debate. In 1917, Rule XXII was amended to allow for ending debate (invoking "cloture") with a two-thirds majority, later reduced in 1975 to three-fifths of all senators "duly chosen and sworn" (usually 60).[6] Thus, although a bill might have majority support, a minority of 41 or more senators can still prevent a final vote through endless debate, effectively defeating the bill. This tactic is known as a filibuster.