Me. Rev. Stat. tit. 34-A, § 9608

This agreement shall enter into full force and effect as to a party state when such state has enacted the same into law. A state party to this agreement may withdraw herefrom by enacting a statute repealing the same. However, the withdrawal of any state shall not affect the status of any proceedings already initiated by inmates or by state officers at the time such withdrawal takes effect, nor shall it affect their rights in respect thereof.