The Supermajority Vote in US Congress

For When the Majority Doesn't Quite Rule

USA, Washington DC, Capitol building at dusk
Capitol building, Washington DC. Dennis Flaherty/DigitalVision/Getty Images

A "supermajority vote" is a vote that must exceed the number of votes comprising a "simple majority." For example, a simple majority in the 100-member Senate is 51 votes; while a 2/3 supermajority vote requires 67 votes. In the 435-member House of Representatives, a simple majority is 218 votes; while a 2/3 supermajority requires 290 votes.

Supermajority votes in government are far from a new idea.

The first recorded use of supermajority rule took place in ancient Rome during the 100s BCE. In 1179, Pope Alexander III used a supermajority rule for papal elections at the Third Lateran Council. 

While a supermajority vote can technically be specified as any fraction or percentage greater than one-half ( 50%), commonly used supermajorities include three-fifths (60%), two-thirds (67%), and three-quarters (75%)

When is a Supermajority Vote Required?

By far most measures considered by the U.S. Congress as part of the legislative process require only a simple majority vote for passage. However, some actions, like impeaching presidents or amending the Constitution, are considered so important that they require a supermajority vote.

Measures or actions requiring a supermajority vote:

  • Impeaching: In cases of impeachment of federal officials, the House of Representatives must pass articles of impeachment by a simple majority vote. The Senate then holds a trial to consider the articles of impeachment passed by the House. Actually convicting an individual requires a 2/3 supermajority vote of the members present in the Senate. (Article 1, Section 3)
    • Expelling a Member of Congress: Expelling a member of Congress requires a 2/3 supermajority vote in either the House or Senate. (Article 1, Section 5)
    • Overriding a Veto: Overriding a presidential veto of a bill requires a 2/3 supermajority vote in both the House and Senate. (Article 1, Section 7)
    • Suspending the Rules: Temporarily suspending the rules of debate and voting in the House and Senate requires a 2/3 supermajority vote of the members present. (House and Senate rules)
      • Ending a Filibuster: In the Senate only, passing a motion to invoke "cloture," ending extended debate or a "filibuster" on a measure requires a 3/5 supermajority vote - 60 votes. (Rules of the Senate) Rules of debate in the House of Representatives preclude the possibility of a filibuster.

      Note: On November 21, 2013, the Senate voted to require a simple majority vote of 51 Senators to pass cloture motions ending filibusters on presidential nominations for Cabinet secretary posts and lower federal court judgeships only. See: Senate Democrats Take the ‘Nuclear Option’

      • Amending the Constitution: Congressional approval of a Joint Resolution proposing an amendment to the U.S. Constitution requires a 2/3 majority of those members present and voting in both House and Senate. (Article 5)
      • Ratifying a Treaty: Ratifying treaties requires a 2/3 supermajority vote of the Senate. (Article 2, Section 2)
        • Postponing a Treaty: The Senate may pass a motion to indefinitely postpone its consideration of a treaty by a 2/3 supermajority vote. (Senate rules)
        • Repatriating Rebels: An outgrowth of the Civil War, the 14th Amendment gives Congress the power to allow former rebels to hold office in the U.S. government. Doing so requires a 2/3 supermajority of both the House and Senate. (14th Amendment, Section 3)

          'On-the-Fly' Supermajority Votes

          The parliamentary rules of both the Senate and House of Representatives provide means by which a supermajority vote can be required for the passage of certain measures. These special rules requiring supermajority votes are most often applied to legislation dealing with the federal budget or taxation. The House and Senate draw authority for requiring supermajority votes from Article 1, Section 5 of the Constitution, which states, "Each chamber may determine the Rules of Its Proceedings."

          Supermajority Votes and the Founding Fathers

          In general, the Founding Fathers favored requiring a simple majority vote in legislative decision-making. Most of them, for example, objected to the Articles of Confederation's requirement for a supermajority vote in deciding such questions as coining money, appropriating funds, and determining the size of the army and navy.

          However, the framers of the Constitution also recognized the need for supermajority votes in some cases. In Federalist No. 58, James Madison noted that supermajority votes could serve as a "shield to some particular interests, and another obstacle generally to hasty and partial measures." Hamilton, too, in Federalist No. 73 highlighted the benefits of requiring a supermajority of each chamber to override a presidential veto. "It establishes a salutary check upon the legislative body," he wrote, "calculated to guard the community against the effects of faction, precipitancy, or of any impulse unfriendly to the public good, which may happen to influence a majority of that body."