<P> The Warsaw Pact was established as a balance of power or counterweight to NATO; there was no direct confrontation between them . Instead, the conflict was fought on an ideological basis and in proxy wars . Both NATO and the Warsaw Pact led to the expansion of military forces and their integration into the respective blocs . Its largest military engagement was the Warsaw Pact invasion of Czechoslovakia in August 1968 (with the participation of all Pact nations except Albania, Romania and East Germany), which, in part, resulted in Albania withdrawing from the pact less than a month later . The Pact began to unravel in its entirety with the spread of the Revolutions of 1989 through the Eastern Bloc, beginning with the Solidarity movement in Poland and its electoral success in June 1989 . </P> <P> East Germany withdrew from the Pact in 1990 . On 25 February 1991, the Pact was declared at an end at a meeting of defence and foreign ministers from the six remaining member states in Hungary . The USSR itself was dissolved in December 1991, although most of the former Soviet republics formed the Collective Security Treaty Organization shortly thereafter . Throughout the following 20 years, the seven Warsaw Pact countries outside the USSR each joined NATO (East Germany through its reunification with West Germany; and the Czech and Slovak republics as separate countries). </P> <P> In the Western Bloc, the Warsaw Treaty Organization of Friendship, Cooperation and Mutual Assistance is often called the Warsaw Pact military alliance--abbreviated WAPA, Warpac and WP . Elsewhere, in the former member states, the Warsaw Treaty is known as: </P> <Ul> <Li> Albanian: Pakti i miqësisë, bashkëpunimit dhe i ndihmës së përbashkët </Li> <Li> Belarusian: Дагавор аб дружбе, супрацоўніцтве і ўзаемнай дапамозе <Ul> <Li> Romanized Belarusian: Dagavor ab druzhe, supratsoŭnitstve i ŭzaemnaŭ dapamoze </Li> </Ul> </Li> <Li> Bulgarian: Договор за дружба, сътрудничество и взаимопомощ <Ul> <Li> Romanized Bulgarian: Dogovor za druzhba, satrudnichestvo i vzaimopomosht </Li> </Ul> </Li> <Li> Czech: Smlouva o přátelství, spolupráci a vzájemné pomoci </Li> <Li> Slovak: Zmluva o priateľstve, spolupráci a vzájomnej pomoci </Li> <Li> German: Vertrag über Freundschaft, Zusammenarbeit und gegenseitigen Beistand </Li> <Li> Hungarian: Barátsági, együttműködési és kölcsönös segítségnyújtási szerződés </Li> <Li> Polish: Układ o przyjaźni, współpracy i pomocy wzajemnej </Li> <Li> Romanian: Tratatul de prietenie, cooperare și asistență mutuală </Li> <Li> Russian: Договор о дружбе, сотрудничестве и взаимной помощи <Ul> <Li> Romanized Russian: Dogovor o druzhbe, sotrudnichestve i vzaimnoy pomoshchi </Li> </Ul> </Li> <Li> Ukrainian: Договір про дружбу, співробітництво і взаємну допомогу <Ul> <Li> Romanized Ukrainian: Dogovir pro druzhbu, spivrobitnitstvo i vzaêmnu dopomogu </Li> </Ul> </Li> </Ul>

Which country has been a member of both nato and the warsaw pact