The amendment is proposed by a vote of two-thirds of both houses in Congress and the 2/3 state legislatures call for a national convention. The amendment proposed is ratified by 3/4 (38) of the state's legislatures and when 3/4 (38) states at the conventions agree. ... You only need 2/3 vote of Congress.
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.
Two weeks after the War of 1812 officially ended with the signing of the Treaty of Ghent, U.S. General Andrew Jackson achieves the greatest American victory of the war at the Battle of New Orleans.