The proposal by state Sen. Robert Martwick is intended to fix a technical problem with the Tier 2 pension system, but Martwick said he doesn’t know how much it could cost taxpayers. He said it could be “billions.”

Fifty-six percent of Illinoisans support amending the Illinois Constitution to reform the state’s public pension systems. Illinois has the nation’s least-funded pension plans.

A Chicago civic group suggests either increasing the state’s personal and corporate income taxes for 10 years or implementing a retirement tax to help pay for the state’s worst-in-the-nation pension debt. Here are the problems with that plan.