Moscow answered NATO with a May 1955 eastern alliance
In May 1955 the Soviet Union and seven other Eastern Bloc states signed the Warsaw Treaty of Friendship, Cooperation and Mutual Assistance—a collective defence pact meant as counterweight to NATO. No NATO–Warsaw Pact armies ever fought each other directly; proxies and ideology carried the Cold War instead.
Fear of a remilitarised West Germany pushed Czechoslovak, East German, and Polish leaders toward security talks even before the formal pact. The USSR had floated joining NATO in 1954 after the Berlin Conference and Molotov's pan-European security ideas; Washington and allies refused. British general Hastings Ismay famously argued against admitting the Soviets into the Atlantic club. West German rearmament debates and the failed European Defence Community made Moscow prefer its own alliance architecture instead of Western membership.
Dominated by the Soviet Union, the pact structured Eastern European militaries until the Cold War's end. East Germany left after reunification in 1990. On 25 February 1991 in Hungary, defence and foreign ministers of the six remaining members jointly declared the alliance finished; the USSR itself dissolved that December, removing the hegemon that had enforced the treaty through crises and interventions.
Thus the Warsaw Pact lived as symmetry politics: a mirror to NATO born from rejected Soviet bids for a different European security order, then dismantled when the bloc that sustained it collapsed. Its paperwork outlasted many tank divisions but not the one-party system underneath the uniforms and joint exercises staged for deterrence theatre.
The alliance's heaviest fighting was aimed at its own members. Soviet troops crushed the Hungarian Revolution in November 1956, days after Budapest had briefly renounced membership. In August 1968 every member except Albania and Romania joined the invasion of Czechoslovakia, the pact's largest operation, and Albania formally quit within a month. Romania, which had shaken off satellite status by the early 1960s, later vetoed Mongolia's bid to join, the first time a non-Soviet member blocked a Moscow initiative. Western officials, noting how hastily the treaty had been assembled, dismissed it as a cardboard castle.
Source: Warsaw Pact
