A similar procedure was adopted in the U.S. in response to the actions of isolationist senators who attempted to talk out, or filibuster, a bill to arm U.S. merchant ships. President Woodrow Wilson urged the Senate to change its rules to thwart what he called a "little group of willful men", to which the Senate responded by introducing cloture in the form of Rule 22 on March 8, 1917.
The cloture rule originally required a supermajority of two-thirds of all senators "present and voting" to be considered filibuster-proof. For example, if all 100 Senators voted on a cloture motion, 67 of those votes would have to be for cloture for it to pass; however if some Senators were absent and only 80 Senators voted on a cloture motion, only 54 would have to vote in favor. However, it proved very difficult to achieve this; the Senate tried eleven times between 1927 and 1962 to invoke cloture but failed each time. Filibuster was particularly heavily used by Democratic Senators from Southern states to block civil rights legislation.
In 1975, the Democratic Senate majority, having achieved a net gain of four seats in the 1974 Senate elections to a strength of 61 (with an additional Independent caucusing with them for a total of 62), reduced the necessary supermajority to three-fifths (60 out of 100). However, as a compromise to those who were against the revision, the new rule also changed the requirement for determining the number of votes needed for a cloture motion's passage from those Senators "present and voting" to those Senators "duly chosen and sworn". Thus, 60 votes for cloture would be necessary regardless of whether every Senator voted. The only time a lesser number would become acceptable is when a Senate seat is vacant. (For example, if there were two vacancies in the Senate, thereby making 98 Senators "duly chosen and sworn", it would only take 59 votes for a cloture motion to pass.)
The Senate is a sandbox, and the GOP are the bullies. We the people need health care reform, and the Senators elected to vote in our best interests are going to have to face the bullies. They have already thrown sand (the teabaggers), and now they are throwing punches (the threat of the filibuster). There will be verbal pushing and shoving. Our ears may begin to burn from the repeating of the two talking points... "Freedom" & "Government takeover".