Tariff
A tariff is a tax on imports or exports between sovereign states. It is a form of regulation of foreign trade. It is a policy that taxes foreign products to encourage or protect domestic industry. It helps limit trade deficits. The tariff is historically used to protect infant industries and to allow import substitution industrialization.
Tariff in United States history
Peter Temin, explains a tariff is an expansionary policy, like a devaluation as it diverts demand from foreign to home producers. He notes that exports were 7 percent of GNP in 1929, they fell by 1.5 percent of 1929 GNP in the next two years and the fall was offset by the increase in domestic demand from tariff. He concludes that contrary the popular argument, contractionary effect of the tariff was small. (Temin, P. 1989. "Lessons from the Great Depression", MIT Press, Cambridge, Mass)