<P> Under the new nuclear option proceedings, the majority leader and presiding officer, guided by parliamentary experts, go through a series of choreographed steps in which the leader asserts that the rules do not mean what they say, the presiding officer challenges him, and then the leader calls a vote to overrule the presiding officer, which requires only 51 votes . This effectively ends what had become a 60 - vote requirement for confirmation of a Supreme Court nominee or the passage of legislation . </P> <P> Senator Trent Lott (R - Miss .) first used the term "nuclear option" for this maneuver in March 2003 . The metaphor of a nuclear strike refers to the majority party unilaterally imposing a change to the filibuster rule, which might provoke retaliation by the minority party . The alternative term "constitutional option" is often used with particular regard to confirmation of executive and judicial nominations, on the rationale that the United States Constitution requires these nominations to receive the "advice and consent" of the Senate . Proponents of this term argue that the Constitution implies that the Senate can act by a majority vote unless the Constitution itself requires a supermajority, as it does for certain measures such as the ratification of treaties . By effectively requiring a supermajority of the Senate to fulfill this function, proponents believe that the current Senate practice prevents the body from exercising its constitutional mandate, and that the remedy is therefore the "constitutional option ." </P> <P> The history of the constitutional option can be traced to a 1917 opinion by Senator Thomas J. Walsh, (Democrat of Montana) who contended that the U.S. Constitution provided the basis by which a newly commenced Senate could disregard procedural rules established by previous Senates, and had the right to choose its own procedural rules based on a simple majority vote . The constitutional option was given further support in 1957 by an advisory opinion written by then - Vice President (and thus President of the Senate) Richard Nixon . In his opinion, Nixon stated that the Constitution grants the presiding officer of the Senate the authority to override Senate rules by making a ruling that is then upheld by a majority vote . </P> <P> A series of votes in 1975 have been cited as a precedent for the nuclear option, although some of these were reconsidered shortly thereafter . </P>

When did the senate go to 60 votes