Being on the brink of a renewed protectionist urge in the US, it’s worthwhile to review the history on this kind of policy.
The Tariff Act of 1930 (codified at 19 U.S.C. ch. 4), otherwise known as the Smoot–Hawley Tariff or Hawley–Smoot Tariff, was an act sponsored by Senator Reed Smoot and Representative Willis C. Hawley and signed into law on June 17, 1930. The act raised U.S. tariffs on over 20,000 imported goods.
The tariffs under the act were the second-highest in the U.S. in 100 years, exceeded by a small margin by the Tariff of 1828. The Act and following retaliatory tariffs by America’s trading partners helped reduce American exports and imports by more than half during the Depression; but economists disagree by how much.