"The tariffs under the [Smoot–Hawley Tariff Act of 1930], excluding duty-free imports...were the second highest in United States history, exceeded by only the Tariff of 1828. The Act prompted retaliatory tariffs by Canada and others. The Act and tariffs imposed by America's trading partners in retaliation were major factors of the reduction of American exports and imports by 67% during the Great Depression. Economists and economic historians have a consensus view that the passage of the Smoot–Hawley Tariff worsened the effects of the Great Depression. Irwin (2011) argues that its negative impacts have been real but too often have been exaggerated by economic historians" [1].
https://en.wikipedia.org/wiki/Smoot–Hawley_Tariff_Act#After_...