Question

How isolationist was the United States in the 1920s? Was the dual policy of economic penetration and arms limitation an effective approach?

Answer 1

The US supported limited internationalism. They wanted profit by selling to both sides of the war, but wanted neutrality by placing restrictions and bans on selling arms to either side.

Answer 2

In my opinion; isolationism is never positively effective (just look at North Korea). It only further steepened our economic decline that lead to the great depression in the 1930s, and it lead to us being ambushed by the Japanese at Pearl Harbor (which took us out of our isolationism).