The Smooth Hawley Tariff, enacted in 1930, significantly impacted the Great Depression primarily by inducing retaliatory measures from other countries. As a result of the tariff, which raised duties on hundreds of imported goods to historically high levels, foreign nations began to retaliate by increasing their tariffs on American products. This response led to a decline in international trade and exacerbated the economic downturn, further hurting the American economy.
The other responses listed, such as the claim about unemployment and Hoover's election success, are not accurate in the context of the tariff's impact. Specifically, unemployment did not drop but rather soared during the Great Depression, reaching unprecedented levels, and Hoover did not win a significant victory in the 1932 election; he lost to Franklin D. Roosevelt, who campaigned against the policies of the Hoover administration, including the tariff.
So the most accurate impact of the Smooth Hawley Tariff on the Great Depression is best reflected by the statement: "Countries responded by raising tariffs on American goods, further hurting the American economy."