Isolationism is the foreign policy, adopted by the United States to stay out of European and Asian affairs. This policy was adopted after world war I, the people of the US wanted to stay away from another major war with the thoughts of the huge number of people lost during the first war. The great depression, in the 1930s, was another reason the people wanted to stay out of another war, no one could afford to do anything much less participate in a whole other war. This theory worked for a while. When president Roosevelt came into office Hitler was making his move on other countries and taking them over. He realized that if Hitler took over the British Navy there was no stopping him coming over here and taking over us also. Roosevelt allowed
