Cloture, called closure in many Commonwealth countries and the guillotine in the United Kingdom and Australia, takes its name from the French word clôture. The modern rule was forged in 1881, when Charles Stewart Parnell and the Irish Parliamentary Party used endless amendments and speeches to block Prime Minister William Gladstone’s Protection of Person and Property Bill during the Land War. After sittings of 22 and then 41 hours, Speaker Henry Brand refused to recognize any more Irish members on February 2 and forced a vote. Gladstone moved to formalize the power, Parliament adopted a rule in 1882, and by 1887 it had become the closure motion that today needs at least 100 MPs and the Speaker’s consent. In the United States, a blockade by 12 senators of Woodrow Wilson’s bill to arm merchant ships against German submarines led the Senate to adopt a cloture rule on March 8, 1917, by 76 to 3.

The original two thirds threshold proved nearly impossible to reach: 11 cloture attempts between 1927 and 1962 all failed, as Southern Democrats used the filibuster to block civil rights bills. In 1975 the Senate lowered the bar to three fifths of senators duly chosen and sworn, the familiar 60 votes, and the modern process requires 16 signatures, a ripening period, and up to 30 hours of germane debate. In November 2013 Harry Reid used a point of order and an appeal of the chair’s ruling to set a simple majority for most nominations, and Mitch McConnell extended the same precedent to Supreme Court nominees in April 2017. The story then turns to Canada’s strict closure rule and a 2012 Hong Kong filibuster ended by the council president with no rule on the books.

• The Lord Speaker in the House of Lords has virtually no power to stop debate and can only warn that closure is meant for exceptional circumstances.
• The Senate first used its new cloture rule in 1919 to end debate on the Treaty of Versailles.
• Canada adopted closure in 1913 under Prime Minister Robert Borden to break opposition delays on a naval aid bill.
• Closure invoked on December 15, 1964, ended the Great Canadian Flag Debate and led to the red maple leaf design.
• In Hong Kong on May 17, 2012, after a filibuster of more than 33 hours, the council president cited Standing Order 92 to end debate without a vote.