Since World War II, the relationship between Turkey and the United States has been characterized by complexity and flux; there have been periods of remarkable cooperation, even when significant disagreements existed. Relations between the two countries are never merely bilateral, for the two are also linked to the North Atlantic Treaty Organization (NATO) and the European Union (EU). The relationship between those two organizations is also complicated because of differing core purposes and somewhat differing memberships. Current Turkey-U.S. diplomatic and military relations are more strained than in recent years, but both countries recognize how vital it is to address issues of mutual importance. In mid-2007 the Atlantic Council, Strategic Studies Institute, and German Marshall Fund of the United States jointly organized a conference to discuss the current state of U.S.-Turkish-EU ties and to consider how those relations might be repaired and enhanced.