How did the Soviets take over Eastern Europe?

The Soviets had taken over Eastern Europe by 1948 after they began taking over near the end of the Second World War.

There were three steps that the Soviets used to take over Eastern Europe

1. The Red Army set up anti-nazi governments in the countries which they had liberated and gave local communists control of the government.

2. Rigged elections were held to ensure communist governments stayed in power.

3. Opposition groups were exiled, imprisoned or killed.

How did the United States react?