Amending the Constitution requires approval by two thirds of both houses of Congress and three fourths of the states, a high bar that has been cleared only 27 times in more than two centuries. Each amendment reflects the concerns of its era, from protecting individual liberty after the founding to abolishing slavery after the Civil War, expanding democracy in the Progressive Era, and adjusting presidential succession in the age of the Cold War.
This guide summarizes every amendment in order, grouped by era, with links to a full entry on each.
The First protects religion, speech, press, assembly, and petition. The Second protects the right to bear arms, and the Third bars quartering soldiers. The Fourth limits searches and seizures, the Fifth protects against self-incrimination and double jeopardy and guarantees due process and just compensation, the Sixth guarantees fair criminal trials and counsel, the Seventh preserves civil juries, and the Eighth bars excessive bail and fines and cruel and unusual punishment. The Ninth protects unlisted rights, and the Tenth reserves undelegated powers to the states or the people.
The Eleventh, ratified in 1795, overturned a Supreme Court decision allowing citizens of one state to sue another state in federal court and became the basis of state sovereign immunity. The Twelfth, ratified in 1804 after the electoral tie between Thomas Jefferson and Aaron Burr in 1800, requires electors to cast separate votes for President and Vice President.
A burst of reform produced four amendments in seven years. The Sixteenth, in 1913, allowed a federal income tax. The Seventeenth, also in 1913, provided for the direct election of senators. The Eighteenth, in 1919, established national Prohibition, and the Nineteenth, in 1920, guaranteed women the right to vote.
After the Civil War, three amendments remade the Constitution. The Thirteenth, in 1865, abolished slavery except as punishment for crime. The Fourteenth, in 1868, defined citizenship and guaranteed due process and equal protection against the states, becoming the most litigated part of the Constitution. The Fifteenth, in 1870, barred racial discrimination in voting, a promise not fully enforced until the Voting Rights Act of 1965.
The Twentieth, in 1933, moved the start of presidential terms to January 20 and congressional terms to January 3, shortening lame-duck periods. The Twenty-first, the same year, repealed Prohibition. The Twenty-second, in 1951, limited Presidents to two terms after Franklin Roosevelt won four. The Twenty-third, in 1961, gave the District of Columbia presidential electors, the Twenty-fourth, in 1964, banned poll taxes in federal elections, and the Twenty-fifth, in 1967, set rules for presidential disability and filling a vacant vice presidency.
The Twenty-sixth, ratified in a record of about 100 days in 1971, lowered the voting age to 18. The Twenty-seventh, which delays any change in congressional pay until after the next House election, was one of Madison's original proposals in 1789. A college student's campaign revived it in the 1980s, and it was ratified in 1992. No amendment has been added since, though thousands have been proposed.
Go deeper on the first ten in the Bill of Rights, amendment by amendment, learn how amendments are adopted in how the Constitution is amended, or read the original seven articles in the Constitution, article by article.