The only Senate process (other than a unanimous consent agreement) to bring debate on a measure to a close, without also simultaneously rejecting the measure. This process is used to end a filibuster by one or more Senators with a supermajority 60-vote threshold.
An Unexpected Journey
Cloture has its origins in 18th century revolutionary France (hence its nickname, "the guillotine"), although it was not used in the United States until nearly a century ago. In the early days of the Republic, members of both the House and Senate were allowed an unrestricted right to obstruct the progression of legislation through the use of the filibuster. While the debate rights of individual members of the House have been sharply curtailed over time, the right of any Senator to object in the Senate has remained mostly unaltered.
One of the most significant restrictions of an individual Senator's power came at the request of President Woodrow Wilson in 1917 and culminated in the Senate adoption of Rule 22. Rule 22 originally stated that a two-thirds majority vote could be used to end debate on a measure or treaty. In the 1950s, its use was extended to end debate on presidential executive branch and independent agency nominations and for Supreme Court nominations. The first request for cloture came in response to a 23-day filibuster of a proposal to arm American merchant ships during World War I. Cloture was first invoked two years later to end a filibuster on the ratification of the peace treaty ending World War I.
The Desolation of Congress
A cloture motion made on a piece of legislation, amendment, or nomination must be submitted with the support of 16 Senators and lays dormant and cannot be voted on until the second calendar day after the motion has been filed, unless waived by unanimous consent. If adopted, cloture limits post-cloture debate to a maximum of 30 hours.
Cloture process has seen some changes over the last century. For instance, in 1975, the threshold was reduced to the present three-fifths majority (or 60 votes) due to a desire of Congress to clean up Washington post-Watergate. Additionally, in 2013, Senate Majority Leader Reid (D-NV) elected to use the "nuclear option" to change Senate rules to allow for a bare majority (51 votes) to end debate on executive branch and judicial nominees, excluding nominations to the Supreme Court.
The Battle of the Two Parties
The last decade has seen the use of the filibuster reemerge as a way to stymie the majority party in control of the Senate as well as the current President's administrative priorities. The 113th Congress (2013-2014) saw over 250 cloture motions filed to end filibusters. In comparison, 200 cloture motions were filed in total between the rule's creation in 1917 and 1980. So far, the 114th Congress has seen 35 cloture motions filed. There has been debate among the Republican presidential candidates whether to repeal the filibuster - and cloture - altogether in order to speed the path towards repealing the Affordable Care Act. On Monday evening, Senate Majority Leader McConnell (R-KY) filed cloture on the Senate's bill to replace No Child Left Behind, signaling that a final vote on its passage could come as early as today.