In The Juridical Nature of Unilateral Acts of States in International Law Eva Kassoti explores the question of the legal nature of unilateral acts by focusing on their essential characteristics, namely unilateralism and the manifest intention to be bound. By analysing the legal and factual context surrounding the making of unilateral acts, this volume offers a list of indicators of the elements of unilateralism and manifest intention that will facilitate the determination of the existence of a unilateral juridical act in practice. Kassoti explores the legal nature of unilateral acts from the viewpoint of the theory of international juridical acts and thus, attests to the validity of this theory as a comprehensive framework for the analysis of all juridical acts in international law.

In Unilateral Acts of States in Public International Law Przemysław Saganek discusses one of the most important sources of States’ obligations in international law. He analyzes in a critical way the classical catalogue of unilateral acts comprising: promise, waiver, recognition and protest. He convincingly proves that this list is misleading as it oversees several important acts of States. On the other hand, several classical acts do not necessarily give rise to legal effects or are not necessarily unilateral. The author undertakes a thorough analysis of several types of acts, showing their similarities and dissimilarities. He concludes that the group category of ‘unilateral acts’ covers such diverse elements that they could be hardly codified in a single set of rules.

Textbooks on international law, dicta of the International Court of Justice and the International Law Commission's 'Guiding Principles applicable to unilateral declarations of states capable of creating legal obligations' of 2006, all reflect the fact that in international law a state's unilateral declaration can create a legally binding obligation. Unilateral declarations are common, as a look at the weekly headlines of any major newspaper will reveal. Many of the declarations made at the highest level are, of course, vaguely expressed and carry no tangible legal commitment. But others deliver a very clear message: for instance the US's April 2010 declaration on its future use of nuclear weapons or Kosovo's declaration of independence and pledge to follow the Ahtisaari Plan, are two recent and prominent examples of unilateral declarations at the international level. The same sources, however, also reveal that while state promises are accepted as a means for states to create full blown legal commitments, the law governing such declarations is far from clear. This monograph fills a gap in international legal scholarship by raising and answering the question of the precise legal value of such pledges in the realm of public international law. After a brief introduction state promises in international law are defined and contrasted with other unilateral acts of states, and the history of promises in state practice and court decisions is delineated, together with scholarly opinion. The book then provides a detailed picture of the international legal framework governing promises of states, and ends with a brief assessment of the raison d'être for promises as a binding mechanism in international law, along with their advantages and disadvantages in comparison with the classical mechanism for assuming international obligations - the international treaty. This is currently the only book to present a comprehensive overview of the legal effect of promises by states in international law.

We are in a moment where peoples and states are interested, directly or indirectly, in asserting their "national interest," unilaterally if necessary. In the White House, the national security policy is premised on "America First," while Catalans and Iraqi Kurds have taken steps to unilaterally declare their independence. All of these actions have generated tension both domestically and internationally. However, even though the potential for unilateral action has been receiving a lot of attention, the larger issue of the legality of unilateral acts is often hard to discern. This book provides a history of the doctrine of unilateral acts in international law, tracing their treatment in the international sphere from consent based acts, to obligations erga omnes, to acts of estoppel. ? Through chapter-by-chapter case studies, this book traces the "legalization" of the category of unilateral acts from its 19th Century foundations into a broad category of obligation. To understand why and how this occurred, this book examines the history of the legal doctrine of unilateral acts, which shows that in spite of efforts to progressively make unilateral acts "legal" they are still not precisely defined or easy to apply, challenging the very commitment these acts are meant to establish.

Because of its unique nature, the sources of international law are not always easy to identify and interpret. This book provides an ideal introduction to these sources for anyone needing to better understand where international law comes from. As well as looking at treaties and custom, the book will look at more modern and controversial sources.

Many different, and even opposite, meanings are ascribed to the term `sources' of international law. The author of this work goes back to the meaning of the term `source' in general (spring or well) and analyses in detail the various sources of international law. He first explains the sources of general, and then those of particular international law. He starts with general principles of law, which is followed by common features of customary process of whatsoever kind, and then by general and by particular customary law. Custom will be followed by unilateral acts of States and with opposable situations in international law which are closely linked with this kind of sources of international law. The explanation ends with treaties in regard to which there are the least doctrinal controversies. The explanation cannot be quite homogeneous. There are still deep doctrinal misunderstandings in respect to general principles of law and of unilateral acts of States. The author therefore offers a critical analysis of representative views of other authors and tries to reach solutions to problems presented. He also gives a systematic explanation of recent pronouncements of international courts and tribunals with regard to customary law, and he examines the specific solutions prescribed in the 1969 Vienna Convention on the Law of Treaties.