Limits of the income tax

Writing in today's Wall Street Journal, Alan Reynolds notes an apparent version of Hauser's Law which applies to income taxes:

From 1951 to 1963, the lowest tax rate was 20% to 22% and the highest was 91% to 92%. The top capital gains tax rate approached 40% in 1976-77. Aside from cyclical swings, however, the ratio of individual income tax receipts to GDP has always remained about 8% of GDP.

The individual income tax brought in 7.8% of GDP from 1952 to 1979 when the top tax rate ranged from 70% to 92%, 8% of GDP from 1993 to 1996 when the top tax rate was 39.6%, and 8.1% from 1988 to 1990 when the highest individual income tax rate was 28%. Mr. Obama's hope that raising only the highest tax rates could keep individual tax receipts well above 9% of GDP has been repeatedly tested for more than six decades. It has always failed.

Federal revenue from the individual income tax exceeded 9% of GDP only eight times in U.S. history—during World War II (9.4% in 1944), the recessions of 1969-70, 1981-82 and 1991-92, and the tech-stock boom-bust of 1998-2001. Revenues were a high share of GDP during the three recessions because GDP fell.

Raising marginal tax rates, particularly on the rich, may not raise much money, but it will make a lot of people feel good.