It wasn't isolationist: the US was a big player in the naval disarmament treaties in the 1920s and early 1930s.
The US in the inter-war period had a very strong pacifist movement, to the point that one member of Congress was unable to vote for the declaration of war on Japan, even after Pearl Harbor.
The US in the inter-war period had a very strong pacifist movement, to the point that one member of Congress was unable to vote for the declaration of war on Japan, even after Pearl Harbor.