Article five of the United States Constitution. "<span>The Congress, whenever </span>two thirds<span> of both Houses shall deem it necessary, shall propose </span>Amendments<span> to this Constitution, or, on the Application of the Legislatures of </span>two thirds<span> 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</span>three fourths<span> of the several States, or by Conventions in </span>three fourths<span> thereof, as the </span>one<span> or the other Mode of Ratification may be proposed by the Congress; Provided that no Amendment which may be made prior to the Year </span>One thousand eight hundred and eight<span> shall in any Manner affect the </span>first<span> and </span>fourth<span> Clauses in the </span>Ninth<span> Section of the </span>first<span> Article; and that no State, without its Consent, shall be deprived of its equal </span>Suffrage<span> in the Senate."
This process has happened 26 times and once unconstitutionally (the 16th amendment) for a total of 27 amendments.
To pass a law, there must be a 51% vote in both houses of Congress, and an approval by the president. Or Congress may override the veto by a two-thirds vote. This has been done well over 40,000 times in 2011 alone. </span>
