10 ILCS 5/23-24
In the case of all constitutional amendments or other questions of public policy submitted to the voters of this State, and of all questions of public policy submitted to the voters of any political subdivision or district, any 5 electors of the State, or of the political subdivision or district, respectively, may contest the results of any such election by filing a written statement in the circuit court within 30 days after the result of the election shall have been determined, in like form as in other cases of contested elections in the circuit court. Such political subdivision shall be made defendant and process shall be served as in suits against such political subdivision; and like proceedings shall be had as in other cases of contested elections before such court. Where the contest relates to a constitutional amendment or other question of public policy submitted to the voters of the State, the statement of contest shall not specify any defendant, but notice of the contest be filed with the Attorney General who may appear and take such steps as he shall deem proper with respect to such contest; the contest may be heard and determined at any time not less than 10 days after notice to the Attorney General as herein provided, and like proceedings as nearly as may be shall be had as in other cases of contested elections before such court.
10 ILCS 5/23-24