In its new strategic concept of November 2010, allies agreed that »as long as nuclear weapons exist, NATO will remain a nuclear alliance.« As clear as this statement appears at first glance, NATO allies continue to debate the role of nuclear weapons. By the same token, NATO agreed at the 2010 Lisbon summit to »develop the capability to defend our populations and territories against ballistic missile attack as a core element of our collective defense,« but allies still differ in their views about the significance and future role of missile defenses. The Lisbon summit declaration adopted a procedural compromise and tasked the NATO Council »to continue to review NATO's overall posture in deterring and defending against the full range of threats to the Alliance.« This procedure became known as the Defense and Deterrence Posture Review (DDPR). Alliance members will use the time until the next NATO summit – scheduled to take place on May 20 and 21, 2012, in Chicago – to consider the appropriate mix of nuclear, conventional and missile defense forces for NATO.