The Introduction sets the stage for the book by explaining the impact of Soviet Union’s collapse in 1991 had on America’s role in the world. Without the perils posed by the USSR, the United States behaved as a liberal hegemon with little constraint. Inspired by Wilsonian idealism and its own post–World War II success, America tried to make the world a better place by militarily invading in a host of nations beset with civil wars, ethnic cleansing, brutal dictators, or devastating humanitarian conditions. It installed democracy and promoted human rights by force of arms for peace and US security interests. So, interventions, regimes, and insurgencies characterized the post–Cold War era. The 9/11 terrorism led America into large-scale incursions and occupations to secure its safety from further assaults by al Qaeda in Afghanistan and from phantom nuclear arms in Iraq. One difference between Cold War era and its immediate aftermath stemmed from the means used by Washington to rid itself of pesky dictators. Before the Berlin Wall disappeared the United States did not want to face a direct confrontation with a nuclear armed Soviet Union. So it turned to the CIA to remove anti-American strongmen in Iran, Guatemala, and Chile with covert operations. When CIA efforts failed to oust dictators after Soviet disappearance, Washington turned to military invasions.

This chapter introduces the debates regarding the development of jus ad bellum, with a particular focus on the development of the definition of force and the right to self-defence. It discusses the relationship between the rules of the UN Charter and customary international law, and the way in which development of custom, as well as debates amongst other international actors, contribute to the dynamic interpretation of the Charter rules.

This chapter focuses on the development of customary international law and unpacks the requirement of publicity for state practice. It introduces the different levels of publicity and covertness, and closely examines the role of acknowledgement, justifications, and public knowledge within the requirement of publicity in the light of various approaches to the development of (customary) international law. The chapter illustrates how the requirement of publicity can be unpacked into two main parts, where the first relates to how a state communicates its understanding of its practice in relation to international law, and the second relates to how the act itself and — if available — the justifications provided for it, are known and reacted to by other states and international actors.

This chapter demonstrates how covert operations differ significantly in their level of publicity, and range from acts that remain secret, to acts that are the object of debates amongst states, legal scholars, and civil society, in and outside the settings of international organisations. It is demonstrated that unacknowledged acts can affect the law in different ways depending on their level of publicity and covertness. It will also be shown that the necessity of the involvement of states in a debate around an operation can vary depending on the rule that it is informing. An unacknowledged act leading to extensive academic debate might prove very informative and play an important role in updating the already vague definition of ‘force’ in light of technological developments, but it would not have the same effect if arguing for a right to preventive self-defence against non-imminent threats, where states have been more active in the debate. It is further argued that the absence of states from certain events and debates opens up more influential participation by other international actors, such as legal scholars and other groups of experts.

This introductory chapter intsroduces the themes, context, and structures of the book.