An international authority is necessary for the features of international legitimacy—that is, international membership, rights holding, fundamental principles of international law and hierarchy of rights holding, and rightful conduct—to be identified and operationalized, to become the expression of legitimacy and legitimacy in action internationally. Since the end of World War II, the United Nations (UN) has embodied this international authority. Having been established by the will of states and the UN Charter, the UN serves as the international authority of the time, the framework in which most of the construction and evolution of international law—be it through lawmaking treaties, the resolutions of the UN Security Council, or the work of the UN General Assembly and other UN organs—has taken place since the end of World War II. In the process, it has played a central role in determining what is and is not legitimate in international life.

In what would turn out to be the twilight decades of early modern Edo, cracks appeared in the foundations of its society and politics. Scholars of Western medicine discovered that the Chinese philosophical ideas that underpinned not just scientific understanding but also morality and the political order could be wrong. The appearance of American warships at the mouth of Edo Bay in 1853 challenged the government and culminated in the signing of humiliating treaties with foreign powers, exacerbating concerns about the shogunate’s ability to govern. And two years later, the fierce Ansei earthquake depleted government coffers, further demonstrated the limits of shogunate power, and fueled popular desires for world renewal. After the Tokugawa regime was toppled in 1868, bringing an end to the early modern order and the very notion of a shogunate, Edo was renamed Tokyo and strategically remade into the capital of an emergent modern nation.

After Cannae, Hannibal needed a maritime base to allow reinforcements and supplies to reach him. But he failed to win over or capture Naples, an old Roman naval ally, and had mixed results elsewhere in Campania: he was successful at proud Capua. He was under-supported from Carthage for all his time in Italy, whether because they could not or would not help him. In 215, he signed a treaty of alliance with Philip V of Macedon. This brought few benefits to either party and would long be remembered by the Romans. Syracuse in Sicily went over to Hannibal in 214 but was recaptured by Claudius Marcellus (late 212). Similarly most of coastal Tarentum in south Italy was in his hands, but only between 212 and 209. In 211, when Capua was under Roman pressure, Hannibal marched on Rome as a diversionary tactic but soon withdrew. Capua fell and was harshly treated.

Ancient communications were slow and precarious, so overseas commanders enjoyed/suffered from partial absence of control by home authorities. Isolation should not be overdone. Literary sources mention official letters home only when remarkable for some reason. Requests to the senate for supplies from Rome were made routinely. Equally, some messages and orders arrived from Carthage. ‘Peripheral imperialism’, far-reaching decisions by men on the spot, are a feature of Roman operations in Iberia. Publius Scipio (father)’s decision to fight the war there is a good example. Other examples are reviewed. Hannibal’s treaty with Philip was co-signed by Carthaginian advisers. Appointment of good subordinates is an important indicator of the quality of a commander’s personal initiatives. Italian Locri is taken as a case study because Hannibal and Scipio both made decisions affecting it. Hannibal’s appointee Hamilcar was guilty of long-term arrogance but was perhaps not as bad as Scipio’s scandalous lieutenant Quintus Pleminius.

International organizations are established by international treaties that set out their powers and limits and the obligations toward international institutions even though few such institutions have the power to enforce their decisions. The politics of international organizations therefore arises in the dynamic between obligation, compliance, and enforcement.

This chapter examines two ways the customary norm could have emerged post-1945: the two-element approach or that article 2(4) gave rise to a new customary rule of its own impact, following the approach of the ICJ in the North Sea Continental Shelf Cases. It demonstrates the challenges of applying the two-element approach to the customary prohibition of the use of force due to the presence of the parallel and near-universal treaty obligation in article 2(4) of the UN Charter, which makes it difficult to identify sufficient relevant State practice and opinio juris outside the treaty. Establishing evidence of the customary rule and its content in this way depends on a number of theoretical issues that remain unsettled or over which significant controversy exists. This chapter then applies the criteria set out by the ICJ in the North Sea Continental Shelf Cases to article 2(4) and argues that article 2(4) meets this test. This chapter concludes that, in contrast to the right to self-defence in article 51 of the UN Charter which explicitly has its origins in customary international law, article 2(4) is itself the origin of the customary international law prohibition of the use of force.

Chapter 2 analyses the negotiation of the WHO Framework Convention on Tobacco Control (FCTC, 1998–2003). It illustrates that evidence was a key element of the negotiations and argues that the FCTC was developed as an evidence-based treaty to counteract the attacks on evidence by the tobacco industry. After a historical introduction, Section 2.2 outlines the theoretical background of the chapter, introducing the notion of ‘treaty entrepreneurs’. Sections 2.3, 2.4, and 2.5 proceed to delineate and analyse how the strategy on evidence unfolded during the FCTC negotiations. Section 2.3 illustrates how legal expertise from international environmental law was borrowed to build a treaty that could embed and develop evidence. Section 2.4 describes how evidence was mobilised to build the treaty. First, the treaty entrepreneurs relied on existing knowledge within the WHO; second, they served as a catalyst for the production of additional evidence from other relevant actors, most notably the World Bank. Section 2.5 reviews how the treaty entrepreneurs framed the available evidence and how the label ‘evidence-based’ started being used. Section 2.6, finally, draws some conclusions on the implications of adopting a strategy on evidence to push forward the negotiations of a treaty.

Æthelweard, the writer of the Chronicle, is mentioned in this Treaty, made between Æthelred the Unready and the Viking leaders in the early 990s after a period of disastrous attacks by the Danes in England. A set of agreed rules as to behaviour between the English and the Vikings is listed. Sigeric, Archbishop of Canterbury is also mentioned. The text contains a number of Old English words and Latin words created from Old English.

The author explores how consent functions as commitment, content, and constitution for international agreements. He argues that consent constructs all forms of international commitment. Consent elucidates an agreement’s contents – what the agreement ‘is’ in terms of scope and substance. Consent can also function as a constitution – delimiting not only ‘primary’ rules encapsulated by an agreement’s existence and contents, but ‘secondary rules’ determining who can make agreements, how they must do so, and ways to recognize, adjust, and end them. For all these functions, consent remains an under-examined and undifferentiated concept. Today, almost any of consent’s functions can be established by almost any formal or informal means. Alongside existing proposals (presumptions/defaults and content-based criteria), this chapter proposes that international law should pursue more – and different – formalities for consent. Having different forms of consent follow its different functions may, according to the author, improve the efficacy of consent and with it the efficacy of international agreements overall.

The author argues that while State consent does contribute to international law’s legitimacy, it does not do so by providing a justification for it. States are not bound to obey international law because they have chosen to submit to its authority. Rather, international law provides them with a reason for action, and indeed they have a moral duty to obey it, if and only if they will do better at realizing justice if they act as the law directs them to act than if they act on their own judgment. As a means for crafting international law, State consent is, according to the author, valuable insofar as it yields international legal norms that satisfy this condition. He argues, that in a few cases, it may also constitute an intrinsically valuable expression of trust in the international political community or an international institution that exercises political authority.

Global environmental meetings provide a locale for understanding how multilateral environmental agreements (MEAs) become words on paper that shape international practices and norms. These meetings are central sites of global environmental agreement-making because they provide diverse actors with a negotiation space and process for the development of treaty text. This chapter provides practical guidance to those who attend, observe, and collect data at MEA negotiation sites. It will help researchers design and implement their studies, and situate their academic work into the negotiation process. Scholars, students, and observers at all stages of their careers will find this chapter useful when preparing to attend a MEA supreme body meeting, navigating on-site, and working to understand and analyze their observations afterward. It can also help when choosing whether to attend in person or not, highlighting the digital resources now available that make that decision even easier. In sum, by unpacking the multiple actors, sites, and processes through which environmental agreements are made and the new arrangements these create, this chapter helps the reader find the appropriate site for their research and navigate the events more confidently.

Before the 20th century, most rules of international law were in the form of customary international law. Since then, the increased complexity of international relations and rapid international development have led to a substantial growth in the number and diversity of treaties. Article 38(1)(a) of the Statute of the International Court of Justice (‘ICJ Statute’) recognises treaties as a (material) source of international law by referring to ‘international conventions, whether general or particular, establishing rules expressly recognized by the contesting states’. Treaties now regulate trade, communications, environmental protection, military cooperation and defence, and human rights, to name but a few of the myriad topics. International environmental law, for example, is almost entirely governed by treaties, and international trade, investment and communications ‘are unimaginable without treaties’. The main rules in the law of treaties are contained in the 1969 Vienna Convention on the Law of Treaties (‘VCLT’), which governs treaty relations between states and is the focus of this chapter.

The chapter analyses each element of the definition of a treaty in the Vienna Convention on the Law of Treaties 1969: an international agreement, concluded between states, in written form, governed by international law, either in a single instrument or in two or more related instruments, whatever its particular designation. Agreements in simplified form such as an exchange of notes or an exchange of letters can also be treaties. The chapter examines the criteria which international courts and tribunals have applied in determining whether other instruments such as agreed minutes might constitute treaties. Relevant factors include: form and designation, terminology, subject matter, terms, context, intent, level of negotiator, definite or conditional terms, clarity, subsequent practice, and registration with the UN. Examples of electronic signature are noted, although state practice is sparse. A treaty should be distinguished from a non-legally binding instrument, such as a memorandum of understanding, although some states use the title ‘Memorandum of Understanding’ also for treaties with a certain subject matter. Unilateral declarations are not treaties but may in some circumstances have binding legal effects. Treaties have a wide variety of titles, including Protocol, but the title does not itself determine whether an instrument is a treaty.

The chapter gives advice on how to draft a treaty, an exchange of notes or a non-legally binding instrument. It goes through all the main components of a treaty text, including the name, preamble, main text, final clauses and testimonium. It covers the drafting of provisions concerning signature, ratification, entry into force and provisional application. It highlights the special considerations which apply to an exchange of notes or letters, including the procedures involved. The second part of the chapter gives practical advice on certain basic drafting techniques.