If 38 states pass the exact same law word for word, then a new amendment can be added to the constitution. This was how the states forced Congress to repeal prohibition. Congress waited until the week that last state was voting on it.

"Article V

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, "