Socially- American ideals such as democracy and freedom made the people feel as though the U.S. could spread those ideals to other countries to ensure peace and promote trade.
Politically- The government would want to gain international attention because it promotes all other assets of a society like the economy and national image.
Militarily- We all know now that the U.S. has the largest and some consider the best military in the world. Though this military was originally created to spread American ideals through imperialism, over time the military became entirely to defend the United States and to promote world peace or intimidate for world peace.
All three of these were heavily boosted by the U.S. being a economical and industrial powerhouse entering and coming out of WW2. When your own nation is prosperous you began to look at others. Also once the U.S. stopped being timid and did not practice isolationism as much it truly became a world power and some might consider the world power.
Adolf Hitler and the Nazi Party came to power during the Great Depression. German workers were laid off and he saw this as his opportunity politically. 1929-1930.
