What communist country rose to international power after world war ii?

The Union of Soviet Socialist Republics  (USSR)

Further details/context:

The United States and the Soviet Union had been on the same side during World War II, members together of the Allies fighting against the Axis Powers.  Following the war, however, the USA and USSR became heated rivals in what came to be known as the Cold War.

Immediate conflicts that caused tension between the USA and the USSR as opposing international powers:

Deeper causes of the tension between the two leading international powers were:

The Soviet Union became a leading international power as the leading Communist nation, aligned against Western democracies.

europeans carried a hidden enemy to the indians: new diseases. native peoples of america had no immunity to the diseases that european explorers and colonists brought with them. diseases such as smallpox, influenza, measles, and even chicken pox proved deadly to american indians