Quote from Business Adventures: Twelve Classic Tales from the World of Wall Street

In 1865 the progressive income tax was eliminated, on grounds that high- and low-income rates unfairly discriminated against wealth.

It (the income tax law) was, however, subjected to a succession of rate reductions and amendments, one of them being the elimination, in 1865, of its progressive rates, on the arresting ground that collecting 10 per cent on high incomes and lower rates on lower incomes constituted undue discrimination against wealth.