Prairie State Wire

After years of trying -- and failing -- to replace Illinois’ flat income tax with a progressive income tax, a constitutional amendment in the state Senate is marking yet another attempt, said the founder of a Chicago-based conservative think tank in a recent newsletter.

"Now, the progressive tax is back. And once again, many lawmakers are selling it as a “tax on the rich,” Illinois Policy Institute Founder and CEO John Tillman said in the newsletter. "But what they don’t want you to know is the constitutional amendment to allow a progressive tax would give lawmakers free rein to change tax rates however and whenever they want. And based on the last proposal, we know they’re coming after the middle class."

Tillman's newsletter arrived shortly after Senate Joint Resolution Constitutional Amendment 1 was filed in the state Senate. Filed by lead sponsor Sen. Don Harmon (D-Oak Park), SJRCA 1 would eliminate Illinois' constitutional flat tax and replace it with a progressive tax based on income. The legislation didn't include a bill or statement describing specific tax rates, which prompted the Illinois Policy Institute to point out that taxpayers in the state would have no way to know how much more they would have to pay under a progressive tax.

Illinois Policy Institute CEO John Tillman | twitter.com/johnmtillman

"In other words, voters are being asked for a blank check that would give politicians the ability to charge different rates to different groups of people without any details on the tax rates," said the Feb. 8 Illinois Policy Institute article written by IPI Director of Budget and Tax Research Adam Schuster.

Crain's Chicago Business warned in December that a progressive income tax would be a tough sell in Illinois, but that apparently isn't discouraging supporters and opponents from speaking up. The Chicago Sun-Times reported in an op-ed piece last week that at least two "dark money" groups, one in favor of the progressive tax and the other against, "are stepping up to separately promote and attack the new governor's agenda."

A progressive income tax has been defeated by "brave Illinoisans" before, Tillman said in his newsletter. "And we're ready to do it again," he added.