Local Leaders were responsible for running the military.
In the late 1800's people in many parts of the world decided to leave their homes and immigrated to the United States
Almost all independence movements took place after WWII. Ghana was the first country in 1957 and by 1965 almost all the countries. The last colonies declared independence in. 1975
1. The empires are gone 2. The wars over religion and territory have stopped 3. Population has skyrocketed