45 ILCS 55/4

The ratification and approval of said compact by this State shall not be binding or obligatory until it shall have been likewise approved by the legislature of any three of the States of Texas, Oklahoma, California, Kansas and New Mexico and by the Congress of the United States. Nothing in this Act or in said compact contained shall be construed as abridging the right of the General Assembly, at any time, to exercise its own discretion as to what laws on the subject matter referred to in said compact it will enact, repeal or amend.