This report and the conference it is based on are motivated by the sharp debate stemming from NATO's decision at Madrid to invite three new members to join its ranks. This debate is not partisan: it cleaves parties. It is profound because it has kindled the first truly geostrategic inquiry among Americans in the post-Cold War era. This inquiry has led Americans to advance from celebrating the end of the Cold War to confronting the design of Eurasia's future security system and America's role in it.