Article 5 is important because, by defining the process for amending the Constitution, it is the basis for that document’s reputation as a “living Constitution”—one that can evolve over time and adapt to circumstances. There are two procedures through which constitutional amendments may be proposed: through Congress or via a convention called by a minimum of two-thirds of the states. Once the Congress passes an amendment, it must be ratified by the legislatures of at least three-fourths of the states. Amendments are ratified and repealed through the same processes. Only the 18th Amendment that enshrined the Prohibition of alcohol in the Constitution has ever been repealed (by the 21st Amendment).