What is an amendment?

An amendment is a formal change or addition to the Constitution made through the procedure set out in Article V. The Founders deliberately built a way to update the document because they understood the original text could not anticipate every future situation. Thomas Jefferson wrote in 1816 that laws and institutions must keep pace with progress of the human mind, and James Madison defended a written amendment process as the only legitimate alternative to violent revolution when fundamental rules need to change.

Article V offers two routes for proposing amendments and two routes for ratifying them. Proposal requires either a two-thirds vote of both the Senate and the House of Representatives, or a convention called by two-thirds of state legislatures, currently 34 of 50. Ratification requires approval by three-fourths of the states, currently 38 of 50, either through their legislatures or through specially called state conventions. Congress chooses which ratification method applies to each proposed amendment.

Only the Twenty-First Amendment, which repealed Prohibition in 1933, has been ratified by state conventions; all the others went through state legislatures. A constitutional convention has never been used; all 27 ratified amendments originated in Congress. The high bar is intentional. It forces broad national consensus that crosses regions, political parties, and majorities of the moment before the basic rules of government change.

Thousands of amendments have been proposed in Congress since 1789, but only 33 have made it past Congress and only 27 have been ratified. Some, like the Bill of Rights, were ratified within months. Others took decades. The Twenty-Seventh Amendment, which delays congressional pay raises until after the next election, was first proposed by James Madison in 1789 and not ratified until 1992, more than 200 years later. Six proposed amendments cleared Congress but failed to win three-fourths of the states, including the Equal Rights Amendment.

An amendment becomes part of the Constitution as soon as the thirty-eighth state ratifies it; once added, it has the same legal force as the original text and overrides any conflicting earlier provision.