The nuclear option is a parliamentary procedure that allows the United States Senate to override a rule or precedent by a simple majority of 51 votes, instead of by a supermajority of 60 votes

The maneuver was brought to prominence in 2005 when Majority Leader Bill Frist (Republican of Tennessee) threatened its use to end Democratic-led filibusters of judicial nominees submitted by President George W. Bush. In response to this threat, Democrats threatened to shut down the Senate and prevent consideration of all routine and legislative Senate business. The ultimate confrontation was prevented by the Gang of 14, a group of seven Democratic and seven Republican Senators, all of whom agreed to oppose the nuclear option and oppose filibusters of judicial nominees, except in extraordinary circumstances.

The nuclear option was raised again following the congressional elections of 2012, this time with Senate Democrats in the majority (but short of a supermajority).[13] The Democrats had been the majority party in the Senate since 2007 but only briefly did they have the 60 votes necessary to halt a filibuster. The Hill reported that Democrats would "likely" use the nuclear option in January 2013 to effect filibuster reform,[14] but the two parties managed to negotiate two packages of amendments to the Rules concerning filibusters that passed on January 24, 2013, by votes of 78 to 16 and 86 to 9,[15] thus avoiding the need for the nuclear option.[16]

In July 2013, the Senate Democratic majority came within hours of using the nuclear option to win confirmation of seven of President Obama's long-delayed executive branch appointments. The ability of the minority party to filibuster appointments was preserved by a last-minute deal in which the White House withdrew two of the nominations in exchange for the other five being brought to the floor for a vote, where they were confirmed.

On November 21, 2013, Senate Democrats used the nuclear option to require only a majority vote to end a filibuster of certain executive and judicial nominees, not including Supreme Court nominees, rather than the 3/5 of votes previously required. A 3/5 supermajority was still required to end filibusters unrelated to those nominees.[17]

On April 6, 2017, Senate Republicans changed the rules to include Supreme Court nominees as part of the "nuclear option".[18] https://en.wikipedia.org/wiki/Nuclear_option

Right...Both sides are like the little kids on the play ground who make up rules after they get out or tagged. We elected these people.