German reunification within NATO in 1990 marked the end of the Cold War. It also cemented America's role as a ‘European power’. By focusing on three key moments in German-American security relations in 1989-90, this essay explains how this outcome materialised. For Chancellor Helmut Kohl, driving the process of unification offered Germans the prospect of international emancipation after four decades of limited sovereignty. For President George H.W. Bush, backing unification proved an opportunity to preserve and transform NATO. Moreover, the new, more political version of the Alliance that emerged became Washington's device to shape the post-Cold War era.