two-thirds

A two-thirds majority is a supermajority voting requirement under which a motion passes only when at least two of every three votes cast (or, in some formulations, two-thirds of the total membership) support it. It is deliberately set above the ordinary 50-percent-plus-one threshold to insulate constitutional amendments, treaty ratifications, removals from high office, and overrides of executive vetoes from transient or narrow majorities. The distinction between "two-thirds of members present and voting" and "two-thirds of the total membership" is decisive: the former is satisfied by a fraction of the house, while the latter demands an absolute supermajority of the entire body. Constitutions specify which formula applies, and that specification is itself frequently litigated and examined.

In the United States, the two-thirds threshold appears repeatedly in the Constitution. Article I, Section 7 requires each chamber to muster two-thirds of members present to override a presidential veto. Article II, Section 2 requires the Senate to ratify treaties by two-thirds of senators present. Article I, Section 3 requires two-thirds of senators present to convict on impeachment, and Article V requires two-thirds of both houses (or two-thirds of state legislatures calling a convention) to propose amendments, with three-fourths of states needed to ratify. In India, Article 368 prescribes that constitutional amendments require a majority of the total membership of each house plus a majority of not less than two-thirds of members present and voting; certain "federal" amendments additionally need ratification by half the state legislatures. Article 61 requires a two-thirds resolution of total membership of each house to impeach the President, and Article 249 lets the Rajya Sabha empower Parliament to legislate on a State List subject by a two-thirds vote of members present and voting.

Named instances illuminate the mechanism. The U.S. Senate's failure to reach two-thirds on the Treaty of Versailles in 1919–1920 kept America out of the League of Nations. The 1868 acquittal of President Andrew Johnson and the 1999 and 2021 acquittals of Presidents Clinton and Trump all turned on the prosecution falling short of sixty-seven Senate votes. In India, the Kesavananda Bharati (1973) ruling held that even the Article 368 two-thirds power cannot alter the Constitution's "basic structure," subordinating the supermajority to an implied limit. As of 2026 these thresholds remain unchanged in both constitutions, and the basic-structure doctrine continues to cap India's amending power.

For exam purposes, the two-thirds rule is high-yield. FSOT (US Government section) tests veto overrides, treaty ratification, impeachment conviction, and the Article V amendment process, often through scenario questions distinguishing "present and voting" from total membership. UPSC (Indian Polity, GS Paper II, and Prelims) repeatedly asks which articles require two-thirds majorities, the precise dual requirement under Article 368, and the interplay with the basic-structure doctrine. Candidates should memorise the exact constitutional citations and be able to differentiate special majority (Article 368) from effective majority and simple majority, since paired-statement and matching questions exploit this confusion.