Two-Thirds of both houses of Congress or two-thirds of the states in convention propse amendments.
ratification
A constitutional amendment would have to be proposed, either by the congress or a constitutional convention, and then the amendment would have to be ratified by three fourths of the states.
Amendments to the U.S. Constitution can be proposed by approval of two-thirds of each house of the U.S. Congress. They can also be proposed by a Constitutional Convention called by two-thirds of states legislatures.
An amendment can be prevented from passing if it does not get enough votes to be proposed (2/3 of both houses in Congress, through a constitutional convention called by 2/3 state legislatures). If an amendment is proposed it can still be prevented from passing by not getting enough votes ( 3/4 of legislatures in states must ratify, or 3/4 of the states must have individual constitutional conventions to ratify it.)
A constitutional amendment is ratified through a process that involves two steps. First, the amendment must be proposed, typically by a two-thirds majority vote in both the House of Representatives and the Senate. Once proposed, the amendment must then be ratified by three-fourths of the state legislatures or by conventions in three-fourths of the states. This process ensures that the amendment has widespread support before becoming part of the Constitution.
The Constitution provides that an amendment may be proposed either by the Congress with a two-thirds majority vote in both the House of Representatives and the Senate or by a constitutional convention called for by two-thirds of the State legislatures. None of the 27 amendments to the Constitution have been proposed by constitutional convention. The Congress proposes an amendment in the form of a joint resolution. Since the President does not have a constitutional role in the amendment process, the joint resolution does not go to the White House for signature or approval. A proposed amendment becomes part of the Constitution as soon as it is ratified by three-fourths of the States (38 of 50 States).
In the US, the legislative branch (Congress) typically votes with a two-thirds majority in both houses to send a proposed constitutional amendment to the states for ratification.
Article V of the US Constitution states that by a vote of two thirds of both houses of Congress an amendment may be proposed to the states for ratification.
According to the U.S. Constitution 3/4 of the various states have to ratify a constitutional amendment proposed to them before it can become permanent part of the Constitution. For an amendment to Acts by Congress, 3/5 of the Senate and 1/2 of the House must agree. The Titles of Nobility amendment did not become the 13th amendment because it was 2 states short. It could still become part of the constitution but it would require the remainer of 38 states to ratify it if it would be enactected now.
The states vote on the amendment.
constitutional amendment by the states
14th amendment