What were the methods the USSR used to impose their control over eastern Europe and how effective were they?

The USSR's influence and domination of Eastern Europe during the 40's and the 50's of the previous century has left indisputable marks upon the region's economic, political and global status, evident still today. As to how this Soviet control was garnered and maintained, and the measure of effectiveness it had, there are two main time periods to examine, namely, Eastern Europe under Stalin, and destalinised Russia under Khrushchev. If control were defined as the "ability …showed first 75 words of 714 total…

…showed last 75 words of 714 total…communist countries were proven efficient as long as he was in power. However, under Khrushchev, most of those binds the USSR had on its lackeys were broken. It cannot be questioned that it was within Khrushchev and the Soviet Union's interest to keep the servile relations the USSR had with nations in its sphere of influence, but the methods that Khrushchev employed were proven futile and gave rise to the subversive restlessness in the 1950s.