In the United States Senate, cloture requires a supermajority of three-fifths. Thus, if a motion has the support of more than one-half, but less than three-fifths, then opponents can stall the Senate by engaging in repetitive debate until concessions are granted; this is a filibuster.
In the United Kingdom Parliament, closure may be adopted in both the House of Commons and in the House of Lords by a simple majority, or more than one-half, of those voting. (In the House of Commons, however, at least one-hundred Members must vote in favour of the motion for cloture to be adopted.) The Speaker of the House of Commons may choose to deny the closure motion if he feels that insufficient debate has occurred, or that the procedure is being used to violate the rights of the minority. In the House of Lords, the Lord Chancellor does not possess an equivalent power.