Supermajority

A supermajority is a voting threshold that is higher than a simple majority, meaning more than half of the votes. It is used to require broader consensus for significant or controversial decisions and to prevent rapid shifts in policy.

Common thresholds include two-thirds (about 66.7%), three-fifths (60%), or four-fifths (80%). Supermajority rules are applied in contexts such as constitutional amendments, treaty ratifications, veto overrides, impeachment, and certain major corporate actions. In some legislatures, a supermajority is required to end debate or invoke certain procedures; for example, in the United States Senate, 60 votes are typically needed to invoke cloture and end debate on most measures, effectively creating a supermajority hurdle. Constitutional amendments, meanwhile, often require two-thirds of both houses to propose and three-fourths of states or similar arrangements to ratify.

Advantages of supermajority rules include encouraging broad consensus, safeguarding minority interests against rash decisions, and promoting stability in long-term policies. Disadvantages include the potential for gridlock, obstruction of timely action, and the excessive bargaining power of a relatively small minority.

Applications vary by system. In national legislatures, they frequently govern amendments, veto overrides, and major appointments or budget decisions. In supranational bodies like the European Union, qualified majority voting uses weighted thresholds to balance sovereignty and efficiency. In corporate governance, supermajority provisions may govern mergers, changes to charters, or other transformative actions. Overall, supermajority rules integrate constraint and deliberation into decision-making in diverse institutions.