The CIA did not do it. The reactionaries in the USSR did it. Kruschev was the beginning of the end. He and his faction wanted to accumulate wealth, so over the decades following his election they progressively built up the mechanisms for wealth accumulation. This is called liberalization, and it’s where the technical definition of Revisionism comes from - making socialism compatible with liberalism. As this process proceeded, the economy stalled out, the inequality got bad, the repression took on an elective component instead of the necessity post revolution and pre world war. Eventually the contradictions sharpened to crisis and the liberals were firmly in charge of most important levers. They dissolved the union and became the new oligarchs.