65 ILCS 5/10-1-27.1

No municipality covered under this Division 1 may make or enforce any rule or ordinance which will in any way inhibit or prohibit any employee from exercising his full political rights to engage in political activities, including the right to petition, make speeches, campaign door to door, and to run for public office, so long as the employee does not use his official position to coerce or influence others and does not engage in these activities while he is at work on duty.