Herbert Hoover signed the Smoot–Hawley Tariff Act during the early years of the 1929 crash.
President Herbert Hoover signed the tariff law on June 17, 1930. It raised U.S. import duties on thousands of goods, making it one of the most protectionist tariff measures in American history. The law was sponsored by Senator Reed Smoot and Representative Willis Hawley, whose names gave it its common title.
The act did not cause the Wall Street Crash of 1929, which had already begun months earlier. However, many economists argue that it worsened the international downturn by provoking retaliatory tariffs and reducing world trade. U.S. exports and imports fell substantially between 1929 and 1933, although the decline also reflected collapsing demand and banking failures. Franklin D. Roosevelt became president in March 1933 and later supported tariff reductions through the Reciprocal Trade Agreements Act. The common mistake is to treat Smoot–Hawley as the original trigger rather than a policy that deepened the crisis.