The Illinois House has endorsed the idea of switching to a graduated income tax.
Democrats who control the House voted 61-52 Tuesday on a resolution calling for the change.
Switching from Illinois' flat income tax would require a constitutional amendment. The earliest voters could consider that would be 2020.
Democratic candidate for governor J.B. Pritzker has called for a progressive tax. It would tax wealthier people at a higher percentage than those with lower incomes. Currently all individuals pay 4.95 percent.
Majority Leader Barbara Flynn Currie says the idea would equalize income distribution. She dismissed Republicans' claims that the wealthy would flee Illinois for lower tax states.
Republicans claim it's also a way for Democrats to gouge taxpayers and raise more money to spend.