What led to the rise of the US as a superpower policeman?

There were two main factors that led to the rise of the US as a “superpower policeman.”  These factors were World War II, which made the US into a superpower, and the Cold War, which motivated it to try to act as a policeman for the world in at least some circumstances.

World War II made the United States into a superpower. The US built its military capabilities up tremendously to fight in this war.  Moreover, the war destroyed all other powers in the world except the Soviet Union.  The war devastated Germany, Japan, France, and to some extent Great Britain. This left the US and the USSR as the only countries that could really become dominant powers in the world. Before the war, the US was no superpower.  After the war, it became one of only two superpowers in the world

After WWII, the US engaged in the Cold War with the Soviet Union.  In this conflict, the US was the leader of the “free world.”  Because it was the superpower that led the non-communist world, the US was expected to maintain some degree of order in that “world.”  The US also wanted to do so as it wanted to keep its allies unified in order to effectively compete with the Soviets.

After the Cold War ended, the US was the world’s only superpower.  As such, it felt responsible for making sure that the world ran properly.  It felt that it was the only country that could maintain peace and order so that the world economy could continue to run smoothly.

In these ways, WWII and the Cold War led the US to become a “superpower policeman”