How did the balance of power formerly embraced by western Europe turn into the balance between the ...

As the Soviet Union retreated from its alliance with the Western powers and turned toward rebuilding communist Russia, it took with it a series of satellite nations across eastern Europe, which Churchill was to term the Iron Curtain. Factoring into this was the policy of decolonization, as Europe was forced to divest itself of imperial powers; yet the USSR found those nations ripe for the introduction of communism, irritating the West. Particularly emblematic of the turn to Eastern and Western bloc status was the formation of the NATO agreements and participation in the Marshall Plan for economic recovery, which was countered by the Warsaw Pact and the prohibition from Moscow of any of the Eastern states participating in the Marshall Plan. Finally, what triggered a significant run of suspicion on the part of each bloc was the development of nuclear weapons and space technology, with neither side wanting the other to get the upper hand.