This monograph examines the United States' position regarding further expansion of the North Atlantic Treaty Organization (NAT0) to include additional countries that were part of the former Warsaw Pact during the Cold War. This process has been evolving since the early 1990s and has already seen Poland, Hungary, and the Czech Republic join the ranks of the alliance in 1999. The purpose of this monograph is to recommend a position that the United States should favor at the 2002 Summit in Prague, where the allies will address further expansion. This monograph begins by analyzing the history of NATO, an alliance that many consider one of the most successful in history, concentrating on NATO's evolving strategy after the dissolution of the Soviet Union and the Warsaw Pact in 1991. This monograph also explains why the United States must stay involved in European affairs and keep Europe as a cornerstone of our national security strategy. This monograph next analyzes lessons learned from previous alliance expansions and how the alliance has helped solve historic differences between countries, as in the case of France and Germany, or perhaps helped them at least avoid war, as in the case of Greece and Turkey. This section also analyzes the impact of the first round of expansion on the alliance and concludes with a brief country overview of each of the nine NATO aspirant countries. This monograph next evaluates the suitability, feasibility, and acceptability of the nine aspirant countries wishing to join the alliance. It concludes that the United States should support an invitation for Slovakia, Slovenia, Romania, Bulgaria, and Macedonia (Former Yugoslav Republic of Macedonia) at the 2002 Summit in Prague. This monograph finds that Albania is not yet politically or economically ready to join the alliance. Additionally, this monograph finds that although the Baltic countries of Estonia, Latvia, and Lithuania are domestically ready to join the alliance, they should not be inv