Arms control agreements present a dual puzzle: states often fail to reach them despite potential mutual benefits, and when agreements do emerge, they vary dramatically in their monitoring provisions – from basic self-reporting to intensive on-site inspections. Approximately 225 multilateral and bilateral agreements have sought to limit military capabilities or behaviors between states. This chapter introduces these empirical patterns and situates them within broader debates in international relations. While political scientists typically associate uncertainty with conflict and instability, this book argues that uncertainty – particularly from domestic political changes – can create opportunities for formal cooperation. The analysis focuses on monitoring provisions as a critical design feature that allows states to detect violations while potentially creating new security vulnerabilities through information exposure. Drawing on both institutionalist and security studies approaches, the book examines how states manage these trade-offs differently under varying conditions. The chapter previews the book’s key contributions: a new theoretical framework linking domestic political volatility to agreement design, comprehensive data on historical arms control agreements, and detailed case studies based on archival materials. This approach offers fresh insights for both scholars studying international cooperation and practitioners confronting contemporary security challenges.

Processes of arms control and disarmament remain relevant in a world where armed conflict between states is still highly visible in international politics, and where civil wars and domestic conflicts claim hundreds of thousands of lives every year. Much attention is focused on the need to control and eliminate weapons of mass destruction (WMDs), especially nuclear weapons, given the hugely destructive nature of these armaments, but controlling so-called ‘conventional weapons’ – those not classed as WMDs – is also important. Conventional weapons, especially small arms and light weapons, are responsible for most of the casualties we see today, even as arms control efforts have only recently begun to focus on these.

This chapter offers a snapshot of detente in a downward spiral, illustrating just how fragile it ultimately proved to be, how susceptible it was to the logic of superpower rivalry, and how utterly dependent it was on domestic variables – especially in the United States. With Nixon's resignation in August 1974, detente – never stable – began to unravel. Crises in Cyprus and Africa, as well as the passage of the Jackson-Vanik amendment, which effectively denied the Soviet Union its Most Favored Nation status and further dampened the already dim prospects for Soviet–American trade, aggravated tensions between Moscow and Washington. Even the successful conclusion of the Helsinki Conference in the summer of 1975 failed to restore trust between the superpowers. Brezhnev's physical and mental decline contributed to a sense of paralysis in Soviet foreign policy. The Cold War returned by default.

This chapter seeks to uncover the origins of New Thinking, with its focus on peaceful coexistence between the East and the West, disarmament, and non-intervention. It argues that while Gorbachev's predecessors sought recognition for the USSR's greatness in the third world, Gorbachev was generally uninterested in maintaining Moscow's reputation as a revolutionary leader. He recognized the Soviet Union's need for reform and aimed to reshape global politics in a way that would allow Moscow to maintain international leadership without overspending on foreign adventures. With the conclusion of the 1987 INF Treaty, Gorbachev demonstrated that disarmament could save money, lessen the dangers of war, and raise Moscow's global standing. However, disentangling from foreign commitments, especially in Afghanistan, proved more complicated. It took a long time to end the conflict in Afghanistan as Gorbachev weighed the moral liability of continued war against considerations of prestige and credibility.

Writing at the beginning of the 1990s on Australia’s disarmament and arms control policies and achievements, Trevor Findlay noted that, although a relative latecomer to the field, Australia had soon become ’an assiduous, well-respected participant ... sporting a range of considered, often imaginative policies and initiatives’. In the main, however, these efforts and initiatives were concentrated in the international arena, with little cross-over into Australia’s domestic political domain. As Findlay described it: ’There is a sense in which Australia has so far tackled, and in most cases accomplished, all the "easy" arms control tasks – those initiatives which can be taken both unilaterally and with relatively little cost to Australia or the government.’ He further added that ’apart from its technical input in the CW area, the Defence Department has so far played only a minor role in shaping Australian disarmament policy,’ and speculated that ’[t]his could change as the international disarmament agenda broadens to include conventional and high-technology weapons that Defence has or plans to acquire’.

This chapter provides a brief overview of China’s engagement with international humanitarian law (IHL) since the late nineteenth century. It first looks back to the late Qing dynasty and follows it through to the early decades of the People’s Republic of China. It then examines China’s contemporary IHL practices, including China’s participation in IHL treaties, its domestic legislations, its approach to IHL training and education, as well as its participation in international rule-making processes. The chapter then focusses on developments of new technologies that have called into question the applicability, relevance and sufficiency of IHL. As IHL is in the process of being adapted, (re)interpreted and expanded, China is seeking to play a more active role in these processes. The chapter concludes with a reflection on China’s changing role and perspectives of its future engagements with IHL.

President Lyndon B. Johnson’s historical legacy in foreign policy is most often associated with the disastrous American military intervention and escalation in Southeast Asia. While the passage of time has not diminished criticism of LBJ’s decision-making in Vietnam, scholars have come to recognize that his administration faced other, often complex international challenges. Some of these issues, like the emergence of a new set of European leaders pursing state interests that often clashed with Johnson’s grand strategic priorities, were of the traditional sort. Other global forces were novel and could not be understood only through a Cold War lens. These new challenges included tense dynamics within the Western alliance, the dilemmas of détente, the aftermath decolonization and the rise of new states, global public health, international monetary relations, and nuclear nonproliferation. This chapter explores how President Johnson navigated some of these complicated, cross-cutting international forces.

This chapter begins the application of Pragmatic Constructivism by interpreting and assessing how, as a community of practice at the macro level, international society has responded to mass atrocity and its challenge to the practices of state sovereignty. It demonstrates how political mobilization on behalf of excluded publics (vulnerable populations) contributed to a reimagining of sovereignty as a responsibility to protect, as well as a normative reassignment of that responsibility to international society when states ‘manifestly fail’. It applies the two tests – inclusionary reflexivity and deliberative practical judgement – to the micro level by assessing the working practices (e.g. penholding, veto reform) of the UN Security Council. While greater inclusivity signposts ways in which the Council can better respond to the public interest, the impact of micro-adaptation is ultimately contingent on a deeper level of change in the identity of member states. Practices of atrocity prevention in the R2P context can act as a pedagogic tool, helping to mobilize the transnational activism that is a necessary part of that progressive change. This discussion extends to nuclear atrocity prevention and the way vulnerable publics deconstructed the Cold War, a lesson that should inform a renewed commitment to deep arms control practices.

This chapter opens with some basic description of and historical background on nuclear weapons. It then develops the basics of nuclear deterrence theory, working through concepts such as mutual assured destruction, first strike capability, second strike capability, first strike instability, the stability–instability paradox, and the nuclear triad. It then works through the causes of nuclear proliferation – the spread of nuclear weapons to new countries – including the logistical details of starting a nuclear weapons program. Relatedly, it examines the tools the international community possesses to slow the spread of nuclear weapons, including the Nuclear Non-Proliferation Treaty, extended deterrence, and economic sanctions, before working through both sides of the debate on whether the spread of nuclear weapons is stabilizing or dangerous. It then asks if nuclear weapons are useful tools of interstate coercion, before examining the conceptual foundations and history of nuclear arms control. The chapter applies many of its concepts to a quantitative study of whether extended deterrence makes allies more likely to start wars, and a case study of North Korea’s nuclear weapons program.

The chapter covers Germany’s perspective on the use of force, armed conflict and international humanitarian law, and arms control and disarmament. The first part addresses Germany’s position on the US killing of Iranian General Soleimani, Germany condemning Iranian missile attacks on US bases in Iraq and Germany refining the right of sustainable self-defence. The second part shows the German Federal Court of Justice reaffirming that there is no justification in international law for attacks by the Kurdistan Worker’s Party, the German government’s stand on foreign troop presence in Syria, Germany’s stand on the law of occupation regarding US forces in Syria, Germany considering Israeli settlement activities in the Occupied Palestinian Territories illegal, Germany’s view on drones, the Federal Constitutional Court affirming only States can claim compensation for violations of international humanitarian law, and the Federal Administrative Court ruling the US may continue to use its base in Germany. The third part covers Germany’s criticism of US anti-personnel landmine policy and Germany’s condemnation of North Korean missile tests.

The period 1919–1935 was a difficult one for Armstrongs and Vickers. With the end of the war domestic and international demand collapsed, and the firms were left with significant excess armament capacity and mounting financial problems. Armstrongs and Vickers responded by diversifying into other businesses, but with limited success. The contraction of the market led the two armaments firms to merge. The Great Depression further eroded military spending and dashed hopes of expanding exports. In the early to mid-1930s three things happened simultaneously: the international situation deteriorated, arms control proceeded but did not solve international insecurity, and there was growing public ire about the past behavior of armament firms. The subsequent Royal Commission into the armament firms cast Vickers in a very negative light and the firms were threatened with nationalization, something neither the firms nor the government wanted. The intervention of Sir Maurice Hankey in defense of the firms proved vital in heading off nationalization. The interwar period was therefore an extended existential crisis for Armstrongs and Vickers.

Wise governance for nuclear weaponry and synthetic biology requires humankind to move more swiftly than today in certain technological domains, while actively slowing down the pace in other areas. For example, advancing technologies for aerial and space-based surveillance, coupled with AI for interpreting the resulting high-resolution images, could allow nations to track in real time the location of other nations’ nuclear missile submarines. Such a development would remove one of the fundamental stabilizing factors in today’s military affairs: the guarantee of a second-strike capability, which lies at the heart of nuclear deterrence. These kinds of technological breakthroughs urgently need to be restrained via diplomatic agreements akin to the superpowers’ arms control treaties during the Cold War. Similarly, the existing “Wild West” in synthetic biology and AI requires swift governmental action to create effective regulatory frameworks for these fields, both within nations and among nations.

This chapter traces Japan’s status concerns from the late 19th century leading up to the 1922 Washington Naval Treaty. It examines Japan’s approach to naval power after the First World War and derives expectations for how Japan would react to an international agreement such as the Washington Naval Treaty from two competing perspectives: material interests and IST. It tests these hypotheses through a detailed account of Japan’s approach to the Washington Conference of 1921–1922. It finds that although Japan faced a growing threat from the United States in the Western Pacific, Japan accepted greater restraints on warship construction in order to maintain its access to the great power club, alongside Britain and the United States, as part of the ‘Big Three’ at the conference. Subsequently, the US Immigration Act of 1924, which unprecedentedly banned Japanese immigration to America, served as a major betrayal of Japan’s sacrifices for the sake of the international order, thus altering Japanese perceptions of the openness and fairness of the Washington system. It convinced many moderates that the West would never consider Japan its equal, and it empowered anti-treaty factions begin the costly process of abrogating Japan’s commitment to the Washington system.

This chapter, which is split into three parts, covers Germany’s perspective on the use of force; armed conflict and international humanitarian law; and arms control and disarmament. The first part discusses the finding of the German Constitutional Court that self-defence against non-State actors is a tenable interpretation of Article 51 of the UN Charter; the Federal Government justifying the fight against ‘ISIL’ in Syria on grounds of collective self-defence; Germany’s take on the legality of the Turkish invasion of north-eastern Syria under international law; Germany backing India’s cross-border strikes against terrorists in Pakistan-administered Kashmir; and Germany’s position that Saudi Arabia was invited to intervene in Yemen. The second part deals with the launch of the Humanitarian Call for Action by France and Germany; Germany opposing the new US position on Israeli settlements in the occupied West Bank; and Germany commenting on the ILC draft principles on the protection of the environment in relation to armed conflict. Germany’s condemnation of DPRK’s missile test is addressed in the last part.