45 ILCS 50/1.8: Article VIII.

Entry Into Force and Withdrawal.)

(a) This compact shall enter into force when enacted into law by any four or more States. Thereafter, this compact shall become effective as to any other State upon its enactment thereof.

(b) Any party State may withdraw from this compact by enacting a statute repealing the same, but no such withdrawal shall take effect until one year after the Governor of the withdrawing State has given notice in writing of the withdrawal to the Governors of all other party States. No withdrawal shall affect any liability already incurred by or chargeable to a party State prior to the time of such withdrawal.