The Smoot-Hawley Tariff Act was a 1930 US law that dramatically increased tariffs on over 20,000 imported goods. Despite intentions to protect American jobs and farmers, it triggered retaliatory tariffs from other countries and is widely considered to have worsened the Great Depression. The Act raised tariff rates to the second-highest level in US history, leading to a 67% reduction in American trade. Despite initial positive economic indicators, the law ultimately contributed to rising unemployment and economic hardship. It was later effectively dismantled through various trade agreements and reforms.
https://en.wikipedia.org/wiki/Smoot%E2%80%93Hawley_Tariff_Act