Book Review of Cezary Mik, Theory of Obligations in International Law

1. The book under review is Cezary Mik, Theory of Obligations in International Law, Routledge Research in International Law, 2024, xiv, + 586 pp., index; ISBN 9781032287423 (Hardback). This book is a rare gem by the publisher, since it is neither a resuscitation of a classic work nor an edited collection. Rather, it is a grand monograph of nearly six hundred pages and it is reminiscent of the style in which theoretical monographs were once written in Eastern Europe, Russia and parts of Germany and the Nordics – lengthy. Moreover, the book is an intellectual feat in itself where the author meticulously navigates the concept of “obligations” in international law and presents his magnum opus not as a fait accompli but actually a mere starting point to excavate the subject matter.

2. The core concern of the book is a theory of obligations which as the author recounts “obligations are, to a large extent, a field concerning the technical […] aspects of relationships between legal subjects” (p.50). The question of legal subjects are necessarily linked to how rules are obeyed in international law and Mik demonstrates especially in Chapter 2 dealing with sources of international obligations that “consent” should be taken into account according to certain conditionalities in order for international rules to be effective: “The assertion that will or consent is the source of international obligations must be relativised to the specificities of the different legal subjects and specificity of particular sources of law” (p. 90). This viewpoint also relates to how Mik examines the role of theories of models of compliance where at times “it is impossible to determine the degree of probability in which they affect the behaviour of legal subjects” (p. 494). These relationships on sources of rules and models of compliance regarding legal subjects in my assessment helps to explain why Mik believes that a theory of obligations “has the potential to enable subjects of international law to behave more rationally” (p. i). The accounts for a theory by Mik are certainly a welcome one and it explores some of the different ways in which international law can function to achieve this. Moreover, Mik also draws on how domestic law is rationally part of the overarching need for a theory of obligations.

3. To get a sense and the depth of the book one need only to immediately turn to the discussions on “types of international obligations” (pp. 158–265) and the opening salvo: “international obligations are not a monolith” (p.158). My observation is that this characterisation of types of obligations summarises the challenges that obligations present both in its terminological sense and the wider meaning of obligations in the international legal sphere. In my view, another challenge is when and how to make states accountable for promises or other guarantees they make at the bilateral and multilateral level. Thus, from my standpoint, these concerns are numerous and there is no one formula to determine obligations but at minimum the practice of international law dictates that customs or contractual reciprocity (treaties) are crucial to typologize obligations. My views however, maybe irrelevant to how Mik’s theory unfolds since in years to come, his contemporaries, critics and admirers will devour, welcome and appreciate what is certainly a disputed topic.

4. The craftmanship and arguments in the book are evident from the very welcome, but simple table of contents which reveals only eight chapters and conclusions. The first four chapters are predictable outlines in that they cover “theory and method”, “sources”, “concept” and “types of international obligations”. From here on, the book gets into a more argumentative phase where “freedom”, “fulfilment”, “feasibility”, and “stability” of obligations are defended. My discretion on the keywords from the short-form table of contents in the book is to illustrate that there is a structured narrative which the book is presenting, and anyone can read a chapter independently and still have a sense of what the whole narrative in the book is about. Occasionally, some parts of different chapters come across as descriptive (and the book overall), and other parts are highly technical and probes how obligations partially sit within different formal sources of international law. The formal sources of international law are embraced and no deviation since tenets such as treaties and customs are relied upon along with the other sources of international law. Hence, if one had expected Mik to reject the formal sources of international law, this was not the case.

5. The attempt to provide a theory of obligations in international law however is no easy task because contemporary international law as we know it (in the West) has settled on what Thirlway refers to as “sources as establishing rules” that provides a definite theoretical compendium.¹ From this perspective, the sources theory is the anchor on which international law is chained and does not necessary call for a new theory to release it from any perceived bondage. Moreover, in recent times the International Law Commission Articles on State Responsibility notes that “every international wrongful act of a State entails the international responsibility of that State.”² In 2024 the International Court of Justice (ICJ) has been preoccupied with a similar question in the request for an advisory opinion on the Obligation of States in Respect of Climate Change.³

6. The above observations then begs the question: if there exists a duty to obey international law, why a (new) theory of obligations? This is a fundamental question which will trouble the reader while attempting to find a rational answer in the book. What however did emerge in precise language is that “the theory of international obligations” in some ways “does not include rules on responsibility for breach of international obligations” (p.49). This kind of argument also exposes the technique of Mik, the need to go beyond existing treatment of, for example, the law on responsibility for international wrongful acts. It should be made clear that Mik’s theory is, after all, about obligations; however, it cannot be separated from concerns about responsibility, and after some contrasting with domestic rules where tort liability for instance is discussed, Mik opines (p. 154) that: “Only responsibility constitutes a structural element of an obligation under international law. At the same time, unlike in private law, where natural obligations are known, international law does not know legal obligations without responsibility.” Mik does not want to fall into the trap of elongating “responsibility” at the expense of this theory of obligations so the relationship between both would require another Lautherpachtian moment on private law analogies. Thus, the “why” factor for a new theory was somehow lost in the defence to the anticipated arguments regarding the existing theories on sources and responsibility for wrongful acts. On the other hand, the “how” factor drew attention to inter alia, “private law analogies” found in domestic legal systems and suggests that “analogy cannot be considered a general principle of international law” (p.18). Thus, if one immediately needs to find the strong point of the book, that is, in my judgement, that analogies to private law renders justice.

7. It is in this fashion that the concept of obligation itself became a bit clear in Chapter 3 where it was linked to private law as a result of “correlated rights and obligations” (p.120). Apart from the analogies of private law with international obligations my main (subjective) interest was “types of international obligations” discussed in Chapter 4 since some views on obligations as a result of bilateral and multilateral relationships were painted. Naturally, any argument about bilateral and multilateral nature of obligations demonstrate one way in which international obligations are borne out for example in international arbitration where incidentally a number of private law analogies are often relied upon. Though not part of the discussions in the chapter, the overall discussions contained in this chapter however makes good reading.

8. This is a book that will appeal to two camps of international lawyers. The first camp being the theorist who craves for a new beginning and argumentation in international law or perhaps who prefers to stay neutral in the great game of international politics which international law legitimates. The second group is the non-Western camp of international lawyers who may find that strands of the theory of obligations appeals to their outlook and practice of international law.

9. This monumental book is evidently the result of years of labour and by some measure an outstanding curation of thought and scope. That in itself is commendable. The book is well researched and contains a great deal of secondary material including from other languages such as French. So, even if it was for Mik to show that through “creative use of existing notions and institutions” (p.47) or to find a “common grammar” (p. 48) for a theory of obligations in international law, his attempts were of value. This does not mean that the reader will walk away satisfied with a new theory of obligations in international law. In any event, Mik should be congratulated on his gigantic effort to intervene in the debate with his valuable attempts and foresights.

Footnotes