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.
Realizing that over time the nation may want to make changes to the Constitution, Article V establishes the amendment process. But unlike laws and regulations, which can be passed or amended by a simple majority of those voting in Congress, the Constitution is difficult to change. An amendment can be offered in one of two ways: when two-thirds of the Senate (67 of 100 senators) and two-thirds of the House of Representatives (290 of 435 representatives) call for a change to be made; or when two-thirds of the states (34 of 50 states) call for a national constitutional convention (a gathering of representatives of each state) to make a change.
Once the amendment is proposed, three-fourths of the state legislatures or state conventions (38 of 50 states) must vote to approve (ratify) the change. An amendment becomes effective when the necessary states have ratified it.
The article also forbids three specific amendments: that would deny a state its votes in the Senate, that before 1808 would enable Congress to prohibit the importation of slaves and that before 1808 would allow direct taxation except as based on the system of enumeration set out in Article I, Section 2. As a result, the three-fifths compromise contained in Article I, Section 9 remained in place until 1808 when Congress banned the international slave trade.