Has the US tax system become effectively a flat tax?
Core argument: The top marginal US federal income tax rate has fallen from over 70% during 1936–1980 to 37% since 2018, part of a broader weakening of progressive taxes.
The top marginal federal income tax rate in the US has significantly decreased from over 70% between 1936 and 1980 to 37% since 2018, reflecting a broader trend of weakening progressive taxes. Corporate taxes, which once accounted for about 50% of corporate profits in the 1950s and 1960s, have declined to 16% by 2018. Estate taxes on large bequests now generate minimal revenue due to high exemption thresholds and numerous deductions. Consequently, the US tax system resembles a flat tax, with most population groups paying rates near the macroeconomic tax rate of 28%. There is mild progressivity up to the top 0.1%, but a significant drop at the top-end, where the top 400 Americans face effective tax rates of just 23%. This shift highlights the diminishing role of traditional progressive taxes in addressing income inequality.























