When the Tea Party movement descends on Chicago's Daley Plaza this afternoon, conservatives like former GOP gubernatorial candidate Adam Andrezejewski and Illinois Policy Institute executive director John Tillman will characterize our state as one that taxes its citizens too aggressively. To commemorate Tax Day, we'd like to remind them of something: In the Land of Lincoln, where our massive budget deficit is growing larger by the day, the income tax structure treats the wealthy extremely well.

First, there's the state's rock-bottom income tax rate.

Of those 41 states that impose an income tax, Illinois's 3 percent rate is the lowest in the nation. And because the constitution mandates that it must be flat, wealthy residents pay the state a far smaller proportion of their income than low- and middle-income earners. When the total tax burden in calculated, the top 1 percent of earners face one of the lowest tax liabilities in the country.  Here's a graph from a report (PDF) by the Insitute on Taxation and Economic Policy that illustrates the relative burden on low- and high-income filers as compared to the other 49 states:

Second, despite our extraordinarily low tax rate, the wealthiest are still sheltering huge amounts of income from the state via tax deductions.

According to our back-of-the-envelope calculations, we think Illinois could be losing as much as $1 billion annually as a result. Yet multiple budget experts can't seem to identify how exactly these rich households are pulling this off.

Finally, the uber-rich here in Illinois are being tossed an additional bone this year.

Because of a quirk in federal law (which we explained in detail here), the state estate tax lapsed on January 1. This levy applies only to select number of wealthy filers. The Commission on Government Forecasting and Accountability reports that, this tax generates $250 to $300 million a year. (In FY 2010, it was $288 million.) "Due to an approximate 9-month delay in estate settlements," they add (PDF), "if a legislative change is not made, revenues would decline approximately $200 million."

The General Assembly could reinstitute it, but we're not aware of any efforts to do so.

If you've been following our budget coverage over the past two years, none of this data will come as a surprise. But as the inaction in Springfield continues, and as the anti-tax rhetoric heats up, it's worth keeping in mind.