Why did American isolation grow after WWI?

Explanation:

... RESULT The USA became isolated from other countries both economically (trade) and politically (by staying out of the affairs of other countries.)

There was an increasing fear of foreign people after WW1. This was due to the war, but mainly the fear that they would take American jobs (because they accepted lower wages.) ... RESULT The USA became isolated from other countries both economically (trade) and politically (by staying out of the affairs of other countries.)8 May 2007

i would say the executive branch is because the executive branch is in charge of enforcing the laws and judicial branch is in charge of enforcing but the executive branch is most responsible for it all so i would have to say the executive branch.