Illinois House Speaker Michael Madigan, D-Chicago, has introduced legislation seeking a constitutional amendment to require a three-fifths supermajority vote of the General Assembly for any future pension benefit increases.
Only a simple majority vote is currently required. The measure calls for the question to be placed on the November ballot.
School districts and local governments would also face the more stringent requirement.
The state is grappling with unfunded pension obligations of $82.9 billion and rising contribution levels.
A working group is expected to report this week to Gov. Pat Quinn on reforms aimed at shoring up the pension system.