Vote Threshold
A vote threshold is the number or share of votes required for an action to pass. Most congressional business needs only a simple majority, but the Constitution and chamber rules set higher thresholds for particular actions: two-thirds of both houses to override a presidential veto, two-thirds of Senators present for treaty ratification and impeachment convictions, two-thirds of both houses (plus three-fourths of states) to propose and ratify constitutional amendments, and three-fifths of the Senate (normally 60 votes) to invoke cloture and end a filibuster.
A vote threshold is the number or share of votes required for an action to pass. Most congressional business needs only a simple majority, but the Constitution and chamber rules set higher thresholds for particular actions: two-thirds of both houses to override a presidential veto, two-thirds of Senators present for treaty ratification and impeachment convictions, two-thirds of both houses (plus three-fourths of states) to propose and ratify constitutional amendments, and three-fifths of the Senate (normally 60 votes) to invoke cloture and end a filibuster.
Example: When the President vetoes a bill, it becomes law only if two-thirds of both the House and Senate vote to override; by contrast, ending Senate debate on most legislation requires three-fifths of Senators duly chosen and sworn — 60 votes under current Senate Rule XXII.
Common misconception: A supermajority threshold does not mean the minority “wins” the vote. Failing to reach the threshold simply means the matter does not pass — the status quo stands until enough votes are assembled.
Sources: The Presentment Clause / veto power, Constitution Annotated; CRS Report 98-425, Cloture, Congressional Research Service