Ratifying an amendment to the U.S. Constitution takes approval from three-fourths of the states, which today means 38 of the 50. That is how constitutional amendments are ratified under Article V, and it is the same threshold whether the states vote through their legislatures or through special ratifying conventions. Congress decides which of those two paths the states will use when it sends the amendment out.1Constitution Annotated. U.S. Constitution Article V
The 38-State Threshold
Three-fourths is a fixed fraction, but the number of states it represents has grown with the country. With 50 states, 38 must ratify. Nothing less counts, and there is no shortcut for amendments that pass by wide margins in the states that do approve. If only 37 states ratify, the amendment fails, even if the other 13 have taken no position at all.
Twenty-seven amendments have cleared this bar in more than two centuries.
Congress Chooses the Ratification Path
Article V gives Congress sole discretion over how the states will vote.2Constitution Annotated. Overview of Article V, Amending the Constitution The joint resolution proposing the amendment specifies one of two methods:
- Ratification by the state legislatures, or
- Ratification by conventions in the states, elected specifically to vote on the amendment.
States do not get to pick. Whichever path Congress writes into the resolution is the path each state must follow.
Ratification by State Legislatures
This is the default. Twenty-six of the 27 ratified amendments went through state legislatures.1Constitution Annotated. U.S. Constitution Article V Each state applies its own internal legislative procedures, and a simple majority vote in both chambers is generally enough.
Two features of ordinary state lawmaking do not carry over. A governor cannot veto a ratification vote. And a state cannot substitute a popular referendum for the legislature’s decision. The Supreme Court settled both points in Hawke v. Smith (1920), holding that ratification “is not an act of legislation, in the proper sense of the word. It is but the expression of the assent of the State to a proposed amendment.” Because that power comes from the federal Constitution, states cannot bolt on procedural requirements the Constitution does not contemplate.3GovInfo. Hawke v. Smith, 253 U.S. 221 (1920) Ohio had tried to put the Eighteenth Amendment to its voters, and the Court struck the effort down.4Legal Information Institute. Hawke v. Smith, 253 U.S. 221 (1920)
Ratification by State Conventions
The alternative path skips the legislatures. Each state instead holds a special election for delegates whose sole job is to meet and cast an up-or-down vote on the proposed amendment. The same three-fourths threshold applies: at least 38 state conventions must approve.
Congress has used this method exactly once, for the Twenty-First Amendment repealing Prohibition in 1933.5Legal Information Institute. Ratification by Conventions The amendment was ratified within the year. The convention route is expensive and logistically demanding, which is part of why Congress has not returned to it.
Time Limits on Ratification
Article V says nothing about how long states have to act. Congress filled that gap starting in 1917 by attaching a seven-year deadline to the Eighteenth Amendment, and nearly every proposed amendment since has carried a similar clock.6Constitution Annotated. Congressional Deadlines for Ratification of an Amendment The Supreme Court blessed the practice in Dillon v. Gloss (1921), reasoning that Congress’s authority to set the mode of ratification implicitly includes authority to set a time limit.7Legal Information Institute. Congressional Deadlines for Ratification of an Amendment
When Congress sets no deadline, an amendment can sit open indefinitely. The Twenty-Seventh Amendment shows what that looks like in practice. First proposed in 1789 alongside the Bill of Rights, it drew only six state ratifications at the time and then went dormant. A University of Texas undergraduate, Gregory Watson, argued in a 1982 term paper that the amendment was still alive because it carried no deadline, and he launched a lobbying campaign that gradually brought more states on board. It became part of the Constitution on May 7, 1992, more than 202 years after it was proposed.8Constitution Annotated. Ratification of the Twenty-Seventh Amendment
Whether an amendment has been ratified within a “reasonable time” is a political question left to Congress, not the courts, under Coleman v. Miller (1939).9Legal Information Institute. From Coleman v. Miller to Baker v. Carr
Can a State Take Back a Ratification?
This question has never been definitively settled. The clearest historical episode came during Reconstruction, when Ohio, New Jersey, and Oregon each voted to withdraw earlier ratifications of the Fourteenth Amendment. Congress refused to recognize the rescissions and declared the amendment ratified. Around the same time, Congress accepted Southern states switching from “no” to “yes.”10Legal Information Institute. Effect of Prior Rejection of an Amendment or Rescission of Ratification
The Supreme Court treated rescission as another political question for Congress in Coleman v. Miller. A federal district court ruled in 1981 that a state should be able to rescind before the three-fourths threshold is reached, on the ground that it would “give a truer picture of local sentiment,” but that ruling was later vacated as moot and carries no binding weight. If the question arises again, Congress will likely be the one to answer it.
When an Amendment Actually Takes Effect
An amendment becomes part of the Constitution at the moment the 38th state ratifies it. Nothing in Washington needs to happen first.11National Archives. Constitutional Amendment Process
The Archivist of the United States then receives the official ratification notices from each state, verifies them, and issues a formal certificate confirming the amendment is valid.12Office of the Law Revision Counsel. 1 USC 106b – Amendments to Constitution That step is administrative, not legal. The proclamation gives public notice to Congress and the country that the process is done, but the amendment’s legal force dates back to the 38th state’s vote. In practice the gap is a matter of days, and during that window the amendment is already enforceable.
The One Thing That Cannot Be Amended
Article V shields a single subject from the amendment process: no state can be deprived of its equal representation in the Senate without its own consent.2Constitution Annotated. Overview of Article V, Amending the Constitution Every other part of the Constitution is open to change if the proposal and ratification thresholds are met.