The most important reason for the collapse of Rome was the failure to actually integrate what they conquered. When Roman soldiers conquered new lands, it was rare that they ever attempted to force their culture, ideals, or laws upon the natives and barbarians. Thus, when the Empire began suffering internal struggles, the natives they had conquered decided to take action, which lead to the swift collapse by barbarian invasion from all sides. It's hard to pick a LEAST important reason, seeing that there were many of them, but I suppose a contender would most likely be the common refusal of the Empire to even acknowledge that barbarians were rising. On the outer edges of their territory, in places like Gaul and Morocco, the Roman government was reluctant to even recognize the threat of the barbarians, thinking that even accepting that these barbarians were causing trouble would weaken their prestige in the public eye.
Nikita Krushchev was the Soviet leader in office during both the Eisenhower and Kennedy presidencies. Kruschev was leader of the Soviet Union from 1953 until 1964.
James Mooney was an American ethnographer who lived for several years among the Cherokee. His most notable works were his ethnographic studies of the Ghost Dance after Sitting Bull's death in 1890
