U.S. President Herbert Hoover signed the Smoot–Hawley Tariff Act into law on June 17, 1930. The tariff's aim was to protect agriculture in the United States, but congressional representatives ultimately raised tariffs on a host of manufactured goods resulting in average duties as high as 53% on over a thousand various goods. Twenty-five trading partners responded in kind by introducing new tariffs on a wide range of U.S. goods. Hoover was pressured and compelled to adhere to the Republican Party's 1928 platform, which sought protective tariffs to alleviate market pressures on the nation's struggling agribusinesses and reduce the domestic unemployment rate. The culmination of the Stock Market Crash of 1929 and the onset of the Great Depression heightened fears, further pressuring Hoover to act on protective policies against the advice of Henry Ford and over 1,000 economists who protested by calling for a veto of the act. Exports from the United States plummeted 60% from 1930 to 1933. Worldwide international trade virtually ground to a halt. The international ramifications of the Smoot-Hawley tariff, comprising protectionist and discriminatory trade policies and bouts of economic nationalism, are credited by economists with prolongment and worldwide propagation of the Great Depression.