---
title: "Two-Thirds Majority Definition | Model Diplomat"
description: "A two-thirds majority requires at least 66.67% of votes, ensuring grave decisions are protected from simple majorities, crucial for constitutional amendments."
url: "https://modeldiplomat.com/learn/glossary/two-thirds"
---

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Model Diplomat Research Team · Last reviewed June 22, 2026

TL;DR

- A two-thirds majority is a supermajority threshold requiring at least 66.
- 67 percent of votes, used in constitutions to entrench grave decisions against simple majorities.
- What is the difference between 'two-thirds of members present and voting' and 'two-thirds of total membership'?
- Which constitutional functions in the U.S. require a two-thirds vote?
- How does the basic-structure doctrine limit India's two-thirds amending power?

[Civil Service & Diplomatic Exams](https://modeldiplomat.com/learn/civil-services/glossary)Updated June 22, 2026

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In February 2021 the U.S. Senate voted 57–43 to convict former President Donald Trump, falling ten votes short of the two-thirds (67-vote) supermajority required under Article I, Section 3, resulting in acquittal.

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