Nuclear option

In the United States Senate, the nuclear, or constitutional, option is when the presiding officer disregards a rule or precedent. The matter then goes immediately to the full senate, which decides by majority vote. This allows the Senate majority to override a requirement for a supermajority. Senate rules require a three fifths, or 60 vote, majority to reach a decision in many situations. In general, the presiding officer follows Senate precedent as interpreted by the parliamentarian. Unlike the speaker of the House, he rarely uses his discretionary power. The nuclear option was used for the first time in 1975 to reform the filibuster, and it was used again in November 2013.