The 1934 Reciprocal Trade Agreements Act (RTAA) changed the structure
of the making of U.S. trade policy and made possible a dramatic reduct
ion in tariffs. The authors demonstrate that the key institutional inn
ovation in the RTAA was its mandate to lower tariffs through reciproca
l agreements with foreign nations. The expansion of exports under the
RTAA enhanced political support for increasingly lower U.S. tariffs. E
vidence that export interests were positively associated with congress
ional votes for free trade supports this view.