The Second World War Marked the Most Substantial Change Ever

The Second World War marked the most substantial change ever in the context in which United States foreign policy is made. The world that emerged after the war had fundamentally changed in economic, political, and military ways. These changes made the world a more dangerous place, and altered the demands placed on foreign policy. What major political change at the end of the Second World War had the greatest effect on United States foreign policy?

A) The emergence of the Soviet Union as a superpower
B) The emergence of China as a superpower
C) The emergence of the United Nations
D) The development of Japanese economic power