The United States Constitution has been amended 27 times since it was ratified in 1788, beginning with the Bill of Rights in 1791 and ending, so far, with a rule on congressional pay ratified in 1992. Those changes did not arrive on a steady schedule. They came in bursts during moments of crisis or reform, separated by long stretches when the text sat untouched.
The Pace of Change
Thousands of amendments have been introduced in Congress since 1789. Only 33 cleared both chambers and went to the states, and only 27 of those were ratified. Once an amendment reaches the states, roughly 82 percent get across the finish line; the harder barrier is getting there at all.
The clustering is striking. Ten amendments were ratified together in 1791. Three followed during Reconstruction between 1865 and 1870. Four arrived in a progressive wave between 1913 and 1920. In between sat long silences, including a roughly 60-year gap between the 12th Amendment in 1804 and the 13th in 1865.
The Bill of Rights (1791)
The first ten amendments were ratified together on December 15, 1791. Several states had refused to approve the Constitution without a guarantee that individual liberties would be shielded from federal overreach. James Madison drafted the proposals, Congress narrowed them from 17 to 12, and the states approved 10.
The list covers ground most Americans can recite in outline: freedom of speech, religion, and the press in the First; the right to bear arms in the Second; protection against unreasonable searches in the Fourth; the right to a jury trial in criminal cases in the Sixth; and a ban on cruel and unusual punishment in the Eighth. The Ninth and Tenth are less famous but do heavy work. They say the people keep rights not listed in the Constitution, and that powers not granted to the federal government belong to the states or the people.
The Reconstruction Amendments (1865–1870)
Three amendments reshaped the country after the Civil War. The 13th abolished slavery. The 14th defined citizenship to include anyone born or naturalized in the United States and guaranteed equal protection under the law. The 15th prohibited denying the vote based on race.
Together they are the largest expansion of constitutional rights since 1791. The 14th Amendment’s equal protection and due process clauses have become some of the most litigated provisions in the entire document, underpinning rulings on school desegregation and marriage equality, among many others.
Voting Rights and the Mechanics of Government
A large share of the remaining amendments broadened who could vote or adjusted how the federal government runs. On voting, the direction has been consistently outward:
- The 19th Amendment (1920) guaranteed women the right to vote after decades of organized suffrage campaigns.
- The 23rd Amendment (1961) gave residents of Washington, D.C. the right to vote in presidential elections, granting the District electoral votes capped at the number held by the least populous state.
- The 24th Amendment (1964) banned poll taxes in federal elections.
- The 26th Amendment (1971) lowered the voting age from 21 to 18. It was the fastest amendment ever ratified, clearing 38 states in just over three months.
Other amendments retooled the government itself. The 20th Amendment (1933) moved the presidential inauguration to January 20 and set congressional terms to begin January 3, shortening the lame-duck period. The 22nd Amendment (1951) capped presidents at two elected terms, a direct response to Franklin Roosevelt’s four consecutive victories. The 25th Amendment (1967) established a clear succession process when a president becomes incapacitated or the vice presidency is vacant.
The One Amendment That Was Repealed
The 18th Amendment (1919) banned the manufacture, sale, and transportation of alcohol. It is the only amendment that restricted individual behavior rather than expanding rights or adjusting government structure. It lasted 14 years. The 21st Amendment repealed it in 1933, and that repeal carries two distinctions of its own: it is the only amendment ratified through state conventions rather than state legislatures, and it is the only time the country has undone a constitutional amendment.
The 27th Amendment’s Long Wait
The most recent amendment, ratified in 1992, prevents any change in congressional pay from taking effect until after the next election of Representatives. It was originally proposed in 1789 as part of the same batch that produced the Bill of Rights, then sat dormant for nearly 203 years. A University of Texas student’s research paper sparked a ratification campaign that finally pushed it over the three-fourths threshold.
The reason such a long wait was even possible: the amendment carried no ratification deadline. Congress began attaching seven-year deadlines starting with the 18th Amendment in 1917, but earlier proposals had no expiration date.
The Amendments That Didn’t Make It
Six of the 33 amendments Congress sent to the states failed to be ratified. Two stand out.
The Equal Rights Amendment, which would have guaranteed equal legal rights regardless of sex, was approved by Congress in 1972 and moved quickly at first. Ratification stalled at 35 states, three short of the required 38. Congress extended the deadline from 1979 to 1982, but the amendment still fell short.
The District of Columbia Voting Rights Amendment, proposed in 1978, would have given D.C. residents full congressional representation. It expired in 1985 with only 16 states having ratified it.
A Note on What the Number Doesn’t Capture
Twenty-seven is the count of formal amendments, and it is the right answer to the question. The practical meaning of the Constitution has also shifted through Supreme Court interpretation, starting with the power of judicial review established in Marbury v. Madison in 1803. Chief Justice John Marshall described the Constitution as marking only its “great outlines,” leaving the details to be worked out over time. So the text has been changed 27 times; the document Americans live under has been reshaped considerably more often than that.