Our country's Founders knew that the U.S. Constitution would need to be able to evolve as the nation grew. So Article V of our Constitution allows for this and spells out the requirements.
As such, and partly because the Founders intentionally wrote language that could be open for future interpretation, changing the U.S. Constitution has happened only 17 times in our country's history since the original 10 amendments, collectively called the Bill of Rights.
Article V says there are two ways to propose a Constitutional amendment:
- A two-thirds majority vote in both the House of Representatives and the Senate in the form of a joint resolution, or
- At a constitutional convention called for by 2/3 of the state legislatures (none of the 27 amendments have been proposed this way).
After that, regardless of the way the amendment was proposed, it must be ratified by three-fourths of the states to become part of the Constitution.
The joint resolution doesn't go to the White House for approval, so the president doesn't have a constitutional role in the amendment process.
Here's the language in Article V of the U.S. 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.