Indiana Code Title 20. Education § 20-38-3-15

A. Any state is eligible to become a member state.

B. This compact becomes effective and binding upon legislative enactment of the compact into law by at least ten (10) of the states. It becomes effective and binding as to any other member state upon enactment of the compact into law by that state. The governors of nonmember states or their designees shall be invited to participate in the activities of the interstate commission on a nonvoting basis before adoption of the compact by all states.

C. The interstate commission may propose amendments to this compact for enactment by the member states. An amendment shall not become effective and binding upon the interstate commission and the member states unless and until the amendment is enacted into law by unanimous consent of the member states.