Since the passage of the 1986 Tax Reform Act, federal tax law has given state lawmakers a clear incentive to rely on income taxes, instead of sales taxes, to fund public investments. This is because state income taxes can be written off by federal taxpayers who itemize their deductions, and sales taxes generally cannot. Even with temporary legislation in place that does allow a sales tax deduction, states that rely heavily on sales taxes — and not at all on income taxes — are essentially choosing to ignore what amounts to a federal "matching grant" for states that rely heavily on progressive income taxes.
A new joint report from ITEP and United for a Fair Economy's Tax Fairness Organizing Collaborative quantifies the cost of this choice in seven states that currently have no broad-based income tax — and that make up the gap by leaning heavily on the sales tax. The report shows that collectively, these seven states could reduce the federal taxes paid by their residents by $1.7 billion a year if they enacted a revenue-neutral reform that replaces sales tax revenue with a flat-rate income tax, and that the same states could save their residents $5.5 billion a year in federal taxes by enacting a similarly revenue-neutral shift to a graduated-rate progressive income tax.