NATO's role (when first founded) was to protect its member countries from the USSR. (Now Russia.) Since the USSR no longer exists, NATO's role is to protect the national sovereignty of its member countries.
It formed the Warsaw pact in 1955
The USSR created their WARSAW Pact to counter NATO.
US/NATO vs USSR/Warsaw Pact.
NATO
NATO was form in 1949
After the USSR collapsed, all of the former Soviet countries remained in a military alliance. This military alliance is called the Commonwealth of Independent States or CIS.
NATO = North Atlantic Treaty Organization; formed in the late 40s by the US and non-Communist Europe to defend against the USSR.
The primary role of NATO was to present a united front against the USSR and its satellites, which for many years had conventional military superiority in Europe.
For the most part the two main protagonists were the US vs. USSR. On a broader scale it was NATO vs. the Soviet Block.
These alliances were formed during the Cold War, our of fear that the USSR would just invade and take over any country which was not part of a powerful alliance that would come to the defense of such a country.
a term used to describe the boundry of the USSR from the NATO countries