Given today's murky geopolitical situation, its always good to cite history as correctly as possible:
"The North Atlantic Treaty Organization (NATO) .. also called the (North) Atlantic Alliance, is an intergovernmental military alliance based on the North Atlantic Treaty which was signed on 4 April 1949."
"The Warsaw Pact was in part a Soviet military reaction to the integration of West Germany into NATO in 1955, per the Paris Pacts of 1954 but was primarily motivated by Soviet desires to maintain control over military forces in Central and Eastern Europe"
OK I stand corrected, NATO was set up first and then the Soviets set up the Warsaw Pact in reaction to NATO. But that still proves my point that NATO was one side, unlike (say) the UN which had/has both sides.
"The North Atlantic Treaty Organization (NATO) .. also called the (North) Atlantic Alliance, is an intergovernmental military alliance based on the North Atlantic Treaty which was signed on 4 April 1949."
"The Warsaw Pact was in part a Soviet military reaction to the integration of West Germany into NATO in 1955, per the Paris Pacts of 1954 but was primarily motivated by Soviet desires to maintain control over military forces in Central and Eastern Europe"
[1] http://en.wikipedia.org/wiki/NATO [2] http://en.wikipedia.org/wiki/Warsaw_Pact