The enlargement of NATO in the 1990s was driven by multiple reasons, but mainly by the strong desire of some former socialist countries to sever all ties with Russia, due to concerns about a potential resurgence of Russia's imperial ambitions. Moreover, the negotiations for NATO accession served as a tool for Eastern European countries to expedite their inclusion into the European Union. The conflict in ex-Yugoslavia also presented a new task for the Atlantic Alliance, which, since its armed intervention in Bosnia, reinvented itself as an instrument for pacification, democratization, and the defense of human rights in Europe and elsewhere. The European Union initially proceeded slowly and cautiously, but the security concerns raised by the conflict in Bosnia likely forced the Union to accelerate the inclusion of Eastern countries. In the beginning, European leaders aimed to include only a few countries, such as Poland and the other members of the Visegrad Group. Finally, in 1997, when the European Union decided to open its doors to all Eastern countries, except Ukraine, the political and economic reforms imposed on the candidate states facilitated their accession to NATO, including the Baltic states. This helped to resolve some political issues, such as the position of minorities within the new democratic states, which could have hindered their inclusion into NATO.