If I recall my history right, the 1929 stock market collapse precipitated the Great Depression, and the tariffs were a (misguided) attempt at trying to set the economy straight.
This ones got a good section on the great depression.
"The imposition of trade barriers in turn resulted in a further deterioration of economic conditions in the countries imposing them, even as their own citizens suffered from these very policies. The governments imposing such barriers, and the economists advocating them, would of course never admit that inflation, increasing centralization, and protectionist policies caused the progressively worsening depression. Instead, political leaders blamed other countries and local ethnic minorities. Years of scapegoating and growing hostility toward foreigners and minorities came to a head in 1939. The world's totalitarian fiat regimes began to turn on each other and on their ethnic minorities. Hayek had identified this threat to global peace in his “Monetary Nationalism and International Stability” lectures in 1937."
In case you are seriously asking this is from Wikipedia.
Intended to bolster domestic employment and manufacturing, the tariffs instead deepened the Depression because the U.S.'s trading partners retaliated with tariffs of their own, leading to U.S. exports and global trade plummeting. Economists and historians widely regard the act as a policy misstep, and it remains a cautionary example of protectionist policy in modern economic debates.