Assurance and US extended deterrence in NATO

Historically the NATO allies have focused considerable attention on US 'extended deterrence'— that is, the extension by Washington of an umbrella of protection, sometimes called a 'nuclear guarantee'. A persisting requirement has been to provide the allies with assurance about the reliability and credibility of this protection. This article examines the definition of 'assurance' used by the US Department of Defense for most of the past decade and argues that it has drawn attention to long-standing policy challenges associated with US extended deterrence in NATO. The article considers the assurance roles of US nuclear forces in Europe, as well as elements of assurance in Washington's relations with its allies regarding extended nuclear deterrence. Whether the allies will retain the current requirements of extended deterrence and assurance in their new Strategic Concept or devise a new approach will be an issue of capital importance in the policy review launched at the Strasbourg/Kehl Summit. Contrasting approaches to these questions are visible in the United States and Germany, among other allies. The main issues to be resolved include reconciling extended deterrence with arms control priorities; managing the divisions in public and expert opinion; and avoiding certain potential consequences of a rupture with established arrangements.