Article Seven of the U.S. Constitution required nine states to ratify it before it took effect.
The article contains the Constitution’s ratification rule: conventions in nine states had to approve the document for it to become established among the states ratifying it. This replaced the Articles of Confederation’s much stricter requirement that all states agree to major changes.
Delaware became the first state to ratify the Constitution on December 7, 1787. New Hampshire became the ninth on June 21, 1788, reaching the threshold specified by Article Seven. The new federal government began operating in 1789.
The Constitution was ultimately ratified by all thirteen original states, although Rhode Island did not approve it until May 29, 1790. Article Seven is therefore about the Constitution’s adoption process, not the number of states that existed or the number of signatures on the document. Its nine-state rule was a major break from the Articles’ unanimity requirement.