Which united states action resulted in the end of isolationist foreign policies?
a. the united states’ entry into world war ii
b. the united states’ entry into world war i
c. the united states’ invasion of vietnam
d. the united states’ annexation of hawaii

It was when U.S. entered in World War II.  After World War I ended, many Americans faced hardships and focused on domestic issues.  Meanwhile, Europe was reeling under the rise of Adolph Hitler and Benito Mussolini.  One by one, countries in Europe were falling to the Germans while in Asia, the Japanese started to take one country after another. U.S. President Franklin Roosevelt realized the dangers of Hitler’s campaign and knew that something had to be done.  Though the Americans have not entered the war, they realized the threat that war posed and through Congress repeal their isolationist policy.  After this they sold weapons to Great Britain through cash to carry method.  They also devised the lend-lease policy to let Britain borrow weapons that would be given  back to the Americans at the war’s end.  Eventually the bombing of Pearl Harbor resulted in the U.S. joining the war and that help defeat the Axis powers.