Nuclear deterrence strategies are predicated on nuclear use scenarios. However, as nuclear weapons haven’t been used since 1945, why does use occur in scenarios but not in practice? If scenarios incorporated the political challenges of crossing the nuclear threshold, how would this change the utility of the deterrence strategies they support? To address these questions, this article examines Cold War-era American debates about a Soviet ‘first strike’, discusses the limits of technical critiques of nuclear use scenarios, and argues for an alternative approach to scenario design and criticism that includes political factors observable in crises and wars involving nuclear states.

The significantly divergent trajectories of terrorism and climate change as security issues for Western states in the early years of the 21st century represent a puzzle. While sharing some attributes – uncertainty and the primacy of risk-management responses – climate change clearly represents a more fundamental threat to life than terrorism. Despite this, terrorism has occupied a prominent place on states’ security agendas, while climate change has been decidedly marginal. This paper explores this divergence. Employing the securitisation framework, the paper maps the approach to terrorism and climate change as ‘security’ issues among key proponents of the ‘war on terror’, before exploring why these two issues were treated in such different ways. This analysis suggests a clear inclination to define and approach terrorism as an urgent security threat necessitating emergency measures: a willingness not evident in the case of climate change. While noting elements of the latter that militated against its securitisation, the paper points to the role of ideology – the beliefs and commitments of political leaders in particular – in driving choices around the construction of the security agenda. It concludes by suggesting that unlike the response to terrorism, impediments to enacting emergency measures to address the climate crisis remain.

Threat perception in international relations has received much academic attention and continues to do so. Other contributions to this special section on how leaders feel security dangers or perceive threats with radical uncertainty are closely intertwined with this article’s focus on threats that are vague and not immediately perceptible. Humans possess a capacity for thinking about and imagining the future known as prospection. Faced with threatening futures, can governments prepare their civil servants to systematically manage uncertainties and anticipate dangers? Drawing on empirical data from interviews with foresight practitioners in the United Kingdom and Singapore, this article examines how governments are nudging civil servants to deploy futures techniques as part of threat perception.

In this article, we analyse the implications of the end of the Cold War for US non-proliferation policy and the non-proliferation regime. Contrary to widely held expectations, we show that the end of bipolarity did not undercut the pursuit of non-proliferation but supercharge it. While bipolarity had afforded non-proliferation hold-outs opportunities to evade superpower pressure, the structural condition of unipolarity both incentivised and enabled the United States to pursue a more robust non-proliferation policy than before. Against the view that contemporary unipolar power is severely circumscribed by the need to make compromises and adhere to social norms, unipolarity allowed the United States to entrench a regime that was widely considered unjust. We support this argument with an analysis of non-proliferation dynamics in the early 1990s, focusing in particular on the process that culminated with the indefinite extension of the Non-proliferation Treaty (NPT) in 1995.

With the decline of the Western framing of the war on terror (WoT) in security discourse, it has become commonplace to note the ‘return’ of great power politics. But under-analysed so far have been the nuclear dimensions of this trend. This is important because we are on the cusp of a multipolar order where the ‘poles of power’ are nuclear-armed. We outline the ways in which almost 30 years of perceptions of unipolarity, and particularly the focus on ‘rogue’ and non-state (nuclear) terrorism post 9/11 on the part of Western policy practitioners, analysts, and scholars, allowed for the previous focus on the threat of nuclear war to be supplanted by a wider ‘nuclear security’ agenda. We unpack the return of nuclear threats and risk-taking in the Euro-Atlantic, the nuclear deterrence balance in the Western Pacific, and the emergence of a non-aligned nuclear great power in the Global South. While we argue that managing the dangers of the return of nuclear great power politics will require a dual approach drawing lessons from both from the Cold War ‘balance of terror’ and from an earlier era of a multipolar ‘balance of power’, many key dynamics from the WoT years remain.

Contemporary reckoning with the catastrophic outcomes of the post-9/11 era opens important questions for the future of counterterrorism policy. It also raises significant issues for thinking through the future priorities and purposes of security scholarship. In this article we make two core claims. First, recent years have seen considerable mainstreaming of ostensibly critical ideas on (counter)terrorism within political debate, media commentary, and – crucially – security policy. Second, such ideas – including around the futility of ‘war’ on terror; the ineffectiveness of torture; the unstable framing of threats such as radicalisation; and the inefficiency of excessive counterterrorism expenditure – were widely dismissed as lacking in policy relevance, even being utopian, when articulated by critically oriented scholars. This development, we argue, raises important ontological questions around the ending of security paradigms such as the war on terror. It also prompts vital political, epistemological, and normative questions around the status of overtly critical scholarship when its ideas and recommendations achieve wider currency.