(Since 2011, federal income taxation has increased under President Barack Obama and declined under President Trump. Data on the full impact of those countervailing changes is not yet available.)

The headline problem is that Congress sharply reduced taxation of the wealthy, cutting top income tax rates as well as corporate and estate taxation.

Meanwhile, the tax burden on everyone else has increased. One reason is the gradual rise of federal payroll taxation, the flat-rate income tax that provides funding for Social Security and Medicare . The Social Security tax is particularly regressive because it applies only to income up to $132,900. The relative scale of state and local taxation also has risen, partly because the federal government increasingly funds its operations with borrowed money rather than tax dollars.

State and local governments rely heavily on sales and property taxes, which impose a greater burden on less affluent households because wealthier people typically spend a smaller share of income on food, housing and other forms of consumption. In roughly one-third of states, this effect is partly offset by progressive income taxation. But even in most of those states, the overall burden still falls more heavily on those with lower incomes. Only a handful of states — California, Delaware, Minnesota, New Jersey and Vermont — and the District of Columbia have written their tax laws so that those with the highest incomes pay the largest share of their incomes.

The Illinois plan is a step in the right direction rather than a complete corrective. Under current law, households in the bottom quintile of the income distribution pay 14.4 percent of their income in taxes on average, while those in the top 1 percent pay 7.4 percent of their income in taxes — a difference of 7 percentage points. The proposed changes in the income tax would cut that gap to 4.3 percentage points, according to the Institute on Taxation and Economic Policy.

Illinois is seeking to address longstanding fiscal problems, notably an underfunded pension system, so it is raising taxes on the rich without significantly reducing taxes for everyone else. Other states, however, could do better by raising taxes on the rich and using the money to reduce the taxation of low-income families.