Procedure for Amending the Constitution of the United States

Article Five of the United States Constitution describes the process whereby the Constitution may be altered. Altering the Constitution consists of proposing an amendment and subsequent ratification.

Amendments may be proposed by either two-thirds of both houses of the United States Congress or by a national convention. This convention can be assembled at the request of the legislatures of at least two-thirds of the several states. To become part of the Constitution, amendments must then be ratified either by approval of the legislatures of three-fourths of the states or ratifying conventions held in three-fourths of the states. Congress has discretion as to which method of ratification should be used. Any amendment so ratified becomes a valid part of the constitution, provided that no state "shall be deprived of its equal Suffrage in the senate," without its consent.  Thus:

To Propose Amendments

Two-thirds of both houses of Congress vote to propose an amendment, or

Two-thirds of the state legislatures ask Congress to call a national convention to propose amendments. (This method has never been used.)

To Ratify Amendments

Three-fourths of the state legislatures approve it, or

Ratifying conventions in three-fourths of the states approve it. This method has been used only once -- to ratify the 21st Amendment -- repealing Prohibition.

The Supreme Court has stated that ratification must be within "some reasonable time after the proposal." Beginning with the 18th amendment, it has been customary for Congress to set a definite period for ratification. In the case of the 18th, 20th, 21st, and 22nd amendments, the period set was 7 years, but there has been no determination as to just how long a "reasonable time" might extend.

Of the thousands of proposals that have been made to amend the Constitution, only 33 obtained the necessary two-thirds vote in Congress. Of those 33, only 27 amendments (including the Bill of Rights) have been ratified.

As stated in the Constitution:

“The Congress, whenever two thirds of both Houses shall deem it necessary, shall propose Amendments to this Constitution, or, on the Application of the Legislatures of two thirds of the several States, shall call a Convention for proposing Amendments, which, in either Case, shall be valid to all Intents and Purposes, as Part of this Constitution, when ratified by the Legislatures of three fourths of the several States or by Conventions in three fourths thereof, as the one or the other Mode of Ratification may be proposed by the Congress; Provided that no Amendment which may be made prior to the Year One thousand eight hundred and eight shall in any Manner affect the first and fourth Clauses in the Ninth Section of the first Article; and that no State, without its Consent, shall be deprived of its equal Suffrage in the Senate."

“The Congress, whenever two thirds of both Houses shall deem it necessary, shall propose Amendments to this Constitution, or, on the Application of the Legislatures of two thirds of the several States, shall call a Convention for proposing Amendments, which, in either Case, shall be valid to all Intents and Purposes, as Part of this Constitution, when ratified by the Legislatures of three fourths of the several States or by Conventions in three fourths thereof, as the one or the other Mode of Ratification may be proposed by the Congress; Provided that no Amendment which may be made prior to the Year One thousand eight hundred and eight shall in any Manner affect the first and fourth Clauses in the Ninth Section of the first Article; and that no State, without its Consent, shall be deprived of its equal Suffrage in the Senate."

"The Congress, whenever two thirds of both Houses shall deem it necessary, shall propose Amendments to this Constitution, or, on the Application of the Legislatures of two thirds of the several States, shall call a Convention for proposing Amendments, which, in either Case, shall be valid to all Intents and Purposes, as Part of this Constitution, when ratified by the Legislatures of three fourths of the several States or by Conventions in three fourths thereof, as the one or the other Mode of Ratification may be proposed by the Congress; Provided that no Amendment which may be made prior to the Year One thousand eight hundred and eight shall in any Manner affect the first and fourth Clauses in the Ninth Section of the first Article; and that no State, without its Consent, shall be deprived of its equal Suffrage in the Senate."