A two-thirds vote in both houses of the United States Congress is required. Three-fourths of state legislatures have ratified it. 2. A two-thirds majority in both houses of the United States Congress Three-fourths of the states have ratification conventions. 2. A two-thirds majority of state legislatures call for a national constitutional convention. Three-fourths of state legislatures have ratified it. 2. A national convention convened by two-thirds of state legislatures. Three-fourths of the states have ratification conventions.
