Question

during which decade did the us pursue a policy of isolationism? 1910s 1920s 1930s 1940s

Explanation:

After World War I, the US pursued isolationism in the 1930s (and also the 1920s to some extent, but more strongly in the 1930s as tensions rose in Europe/Asia but the US sought to avoid involvement). The 1930s saw neutrality acts and a focus on domestic issues, avoiding foreign conflicts. The 1910s had WWI involvement later, 1940s had WWII entry. So the 1930s is the key decade for isolationism here.

Answer:

1930s