On 6 April 2010 the long-awaited nuclear posture review report was released, fulfilling a promise from as the White House blog proclaimed.1 A year earlier, in Prague, President Barack Obama had pledged that the United States would take concrete steps towards a world without nuclear weapons. On the 40th anniversary of the entry into force of the nuclear nonproliferation treaty in March 2010, Obama pledged that the forthcoming review would move beyond outdated Cold War thinking and reduce the number and role of nuclear weapons in US strategy.2 The administration clearly saw the review as a key element of the positive narrative regarding US nuclear nonproliferation and disarmament policy that it wanted to convey prior to the Washington nuclear security summit in April and the nonproliferation treaty review conference in New York in May. Now that these major multilateral events have successfully been held and the anniversary of the review's release has passed, it is worth considering its real impact on the international strategic environment. Did the review represent a genuine reform of US nuclear policy or was it more of a public relations exercise designed to position the US favourably in the context of a major meeting of the nonproliferation treaty parties? This article will consider the review from an international perspective, and in particular how its content responds to the obligations of states party to the treaty and the decisions of its quinquennial review conferences. The review, as an authoritative policy statement of the world's leading nuclear power, was addressed to a foreign as much as a domestic audience. The nature and timing of the review was intended to influence states active in international nuclear affairs in a manner coincident with US policy objectives. Issued a month before the opening of the May 2010 review conference of the nonproliferation treaty, and after a decade of difficulties for this core international security treaty, the nuclear posture review was undoubtedly going to have an impact on the perceptions of participating states as well as on the atmosphere of the conference itself.Despite the timing of its release and its deployment as a public diplomacy vehicle in the lead-up to the US -hosted nuclear security summit and treaty review conference, the nuclear review was nevertheless very much a home-grown product. It had domestic roots as a congressionally mandated review of all aspects of US nuclear weapons policy and posture, as well as the related infrastructure of the nuclear weapons complex. An early decision was taken to issue the review solely in an unclassified form, thus ensuring full transparency of the results to the public, both domestic and foreign. The Obama administration was not going to repeat the mistake of the previous administration, which conducted a classified nuclear posture review in 2001 and saw excerpts of it leaked, including controversial text on nuclear deterrence and preemption that provoked international consternation. The 2010 review was designed to be viewed as a progressive statement on US nuclear weapons policy that would complement the administration's foreign policy aims of strengthening the treaty and enlisting international support in shoring up the global nonproliferation regime. At the same time, it was also meant to send a reassuring message to US allies and partners who rely on extended deterrence that American commitments are as solid as ever. Finally, it was intended to placate various domestic constituencies with vested interests in the continuation of nuclear forces and the associated nuclear weapons complex. Given the inherent tensions, if not downright incompatibility, among these various aims, it is not surprising that in the end the review delivered a rather mixed message to the international audience.The salient issues of the review from an international perspective were the definition of the role for nuclear weapons in US strategy; the nature of the security assurances the US was prepared to give to non-nuclear weapons states; what action the US would take on outstanding nuclear disarmament commitments; what would be done to strengthen nonproliferation and nuclear security; and how the US would approach relations with other nuclear weapons-possessing states. …