I think the dis integration of the USSR was mainly due to internal factors. Power struggle within the communist party and the public was hungry for a change as well, since they were ruled for so long by the same party, they simply wanted to try something else, and you know what, they ended up with a corrupt gov and losing their supoerpower statues.
This is very true. I was lucky enough to find an older man from Ukraine in my workplace who grew up in the USSR. He told me of the degree of shortages, and the discontent of how much the government controlled their lives. If you wanted a better place to live, the government would give it to you if it wanted after a decade of service. you worked where the government told you to work, etc, etc.
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