Amendments to the U.S. Constitution can be proposed by two entities under Article V of the Constitution:

• Congress : An amendment may be proposed when two-thirds of both the House of Representatives and the Senate vote to approve it. This is the only method that has been used so far to propose all 33 amendments sent to the states for ratification

• Constitutional Convention : Congress must call a convention for proposing amendments if requested by the legislatures of two-thirds of the states (currently 34 out of 50). This method has never been used to propose an amendment

After proposal by either method, an amendment becomes valid only when ratified by the legislatures or conventions of three-fourths of the states (currently 38 out of 50)

. The President has no formal role in the amendment proposal process and cannot veto proposed amendments

. In summary, amendments can be proposed either by a two-thirds vote in both houses of Congress or by a constitutional convention called upon request of two-thirds of state legislatures. The congressional proposal method is the only one historically used.