How did the goals of united states foreign policy change from the end of the first world war to the end of the korean war?

At the end of WWI, the United States followed a policy of partial isolationism. After the war, the United States had created the League of Nations but actually never joined. During the Cold War through proxy wars, the United States fought Russia through the Korean and Vietnam conflicts. In the Korean and Vietnam war especially, the United States reaction changed wanting to be more involved amd made forign policy the top of their priority. When north Korea invaded South Korea, the United States jumped in to defend South Korea and Russian allied with North Korea respectively. This exact set up was the same for North and South Vietnam. The US wanted to intervene and this was one of the wars/conflicts that turned the Cold war into a "hot" war. Hope this helps