This chapter summarises the science behind nuclear weapons and describes their development first by the United States and then by the Soviets with a narrative of the nuclear arms race between the two superpowers during the Cold War. Also described are the nuclear weapons programmes of the United Kingdom, France, China, Israel, India, South Africa, Pakistan, and North Korea. Of these, only South Africa has eliminated its programmes and the associated weapons.

These brief concluding remarks look to the future of nuclear arms control and disarmament, but not with great optimism.

Political transitions in a multiethnic setting are often marred with violence between groups. Why does ethnocommunal violence during a country’s democratic transition erupt in some places, and not others? Why does it subsequently decline? Existing explanations typically focus on the weakness of state capacity, the power struggle between political candidates around elections, or the structural factors such as economic inequality between groups. However, in many countries in transition, administrative units with similar characteristics have varying levels of violence. In this book, I build on Albert O. Hirschman’s framework of exit, voice, and loyalty, and I argue that excluded local elites mobilize violence to leverage their demands for greater inclusion in local politics during democratic transition. When these demands are accommodated, violence will decline. This chapter provides an overview of my theory, contributions to related literature, methodological approaches, key findings, and plan of the book.

This chapter describes the use of nuclear weapons and other nuclear explosive devices. To date, the dropping of the two atomic bombs on Japan in August 1945 is the only hostile use of nuclear weapons by one State against another. But in the 1960s to 1980s, around 160 nuclear explosive devices were detonated for so-called ‘peaceful purposes’. Also described is the Cuban missile crisis as well as broken arrow incidents in which major accidents occurred with nuclear weapons.

While nine States in Asia, Europe, and North America retain and modernise their nuclear arsenals, projecting to retain nuclear weapons for the rest of the century, most of the world and beyond is subject to a regional nuclear-weapon-free zone. This chapter describes the different nuclear-weapon-free zones and the global UN ban treaty, which entered into force in January 2021.

Tens of thousands of nuclear weapons of Soviet/Russian and US nuclear weapons have been destroyed under successive bilateral treaties. Only one, New START, remains in force, and only until 2026. This chapter explains why and summarises the content and impact of the main treaties adopted between the two superpowers, beginning with the SALT I and ABM treaties in 1972.

For the last six decades, the NPT, as it is commonly known, has been the legal cornerstone of the global nuclear non-proliferation regime. The rationale for the treaty, its main provisions, and the challenges it has been meeting over the last 25 years in particular are discussed.

This chapter traces the emergence of ethnic cleavages in the Indonesian archipelago, across three time periods: (1) the early modern period, (2) Dutch rule and Japanese occupation (1596–1945), and (3) Soekarno’s regime (1945–1966). It shows that although Indonesians have been accustomed to diversity along various dimensions over the years, ethnicity became relevant as a basis for mobilization when the ruling authorities allocated resources and treated groups differently along ethnic lines. At times, ethnic groups engaged in violence to challenge their treatment by existing authorities. These precedents for using violence to contest existing political configurations and to renegotiate the boundaries of who is “in” or “out” set the stage for the more recent mobilizations of violence during Indonesia’s democratic transition.

Since July 1945, more than 2,000 nuclear explosive devices have been detonated in tests in more than 60 different locations. The total yield of nuclear tests conducted from 1945 to 1995 is equivalent to 34,000 Hiroshima-size bombs. Only North Korea has test-detonated nuclear weapons this century. While the 1963 Partial Test-Ban Treaty remains in force the 1996 Comprehensive Nuclear-Test-Ban Treaty has not entered into force. The chapter explains why and what customary rules restrain nuclear testing today.

This chapter explains the dissipation of violence. Consistent with my theory, once political exclusion was ameliorated in conflict-ridden districts, the level of violence dropped. The creation of new districts and the implementation of direct elections of local executives accommodated these demands for inclusion. Whereas previously excluded political hopefuls faced impenetrable barriers to election, the creation of new districts multiplied the number of elected positions and increased the likelihood of opposition electoral victories, particularly in post-conflict areas where the electorate was already receptive to ethnic appeals and likely to vote for members of their ethnic group.

This chapter discusses the specific relationships between Golkar’s entrenchment, the exclusion of local ethnic elites, and the mobilization of riots in two high-conflict Indonesian provinces, Central Sulawesi and Maluku. By comparing two pairs of districts – Ambon and Maluku Tenggara in Maluku province, and Banggai and Poso in Central Sulawesi province – I demonstrate the importance of local elites’ framing, mobilization, and organization of violence. Although the four districts are relatively similar in their religious and ethnic composition, level of economic development, and dependence on the state, Ambon and Poso experienced some of the most protracted and intense ethnocommunal violence in Indonesia’s recent history, while their two neighboring districts, Maluku Tenggara and Banggai, respectively, were relatively peaceful by comparison. Relying on interviews with bureaucrats, community leaders, and former combatants, I show that these diverging outcomes can be attributed to local elites’ initial political configuration at the onset of the democratic transition, and to their actions and responses to trigger events.