Changes in U.S. Tariffs: Prices or Policies?

In the century after the Civil War, roughly two-thirds of U.S. dutiable imports were subject to specific duties whose ad valorem equivalent was inversely related to the price level. This paper finds that import price fluctuations easily dominate commercial policies (changes in rates of import duty) in bringing about changes in the average U.S. tariff from 1865-1973. About three-quarters of the post-Smoot Hawley decline in U.S. tariffs, for example, can be attributed to higher import prices, the remainder to negotiated reductions in tariff rates.