Article XIII, Section 5 of the Illinois Constitution states: “Membership in any pension or retirement system of the state or any local government, or any agency or instrumentality of either, shall be an enforceable, contractual relationship, the benefits of which shall not be diminished or impaired.” (Helen Kinney and Henry Green were the delegates who jointly “sponsored the pension clause proposal as an amendment to the proposed Legislative Article” at the 1970 Illinois Constitution).
[Added May 8, 2015]: Doris Heaton, et al. v. Pat Quinn, in his capacity as Governor of the State of Illinois, et al.
“…The judgment of the circuit court declaring Public Act 98-599 to be unconstitutional and permanently enjoining its enforcement is affirmed: The concerns of the delegates who drafted article XIII, section 5, and the citizens who ratified it have proven to be well founded. Even with the protections of that provision, the General Assembly has repeatedly attempted to find ways to circumvent its clear and unambiguous prohibition against the diminishment or impairment of the benefits of membership in public retirement systems. Public Act 98-599 is merely the latest assault in this ongoing political battle against public pension rights. As we noted earlier, through that legislation the General Assembly is attempting to do once again exactly what the people of Illinois, through article XIII, section 5, said it has no authority to do and must not do… The judgment of the circuit court declaring Public Act 98-599 to be unconstitutional and permanently enjoining its enforcement is affirmed” (Heaton v. Quinn, 2015 IL 118585).