Illinois has the one of the most unfair tax systems in the United States. In response, Governor J.B. Pritzker and the General Assembly have debated whether to amend the Illinois Constitution to allow the state to replace its flat-rate income tax system with a progressive (or “graduated-rate”) income tax. Illinois is currently one of only eight states that has a flat-rate tax, while 33 states have progressive income tax systems. The Project for Middle Class Renewal (PMCR) at the University of Illinois at Urbana-Champaign and the Illinois Economic Policy Institute (ILEPI) have jointly evaluated the effects of 8 different scenarios for adopting a progressive income tax in the state, including the governor’s proposed “fair tax.” The scenarios are intended to serve as examples for voters and lawmakers. A progressive income tax would transform Illinois’ tax code by bringing middle-class tax burdens down towards rates in neighboring states. Moving to a graduated-rate structure could make the state’s tax code fairer, cut income taxes for working-class and middle-class families, provide opportunities for property tax relief, help balance the budget, and provide revenue to fund essential public services that contribute to the growth of the Illinois economy.