Answer:
The role of United States was of a competitor for the world power, which exhausted Soviet Union in long run.
Step-by-step explanation:
The Soviet Union's vast income from a 2-decade oil boom on an untenable arms race against the United States proved fatal for it. Instead of trying to boost the living standard of the Soviet people, they were more concerned about making nuclear weapons. The promised paradise of workers was vanishing from the eyes of people and they asserted for more autonomy.