"When … decisions are made by authorized persons or organs, in appropriate forums, within the framework of established practices and norms, then what occurs is legal decision-making … international law is a continuing process of authoritative decisions. This view rejects the notion of law merely as the impartial application of rules. International law is the entire decision-making process and not just the reference to the trend of past decisions which are termed ‘rules’".
Higgins, R, Problems and Process: International Law and How we Use it, Oxford, Clarendon Press, 1995.
If international law is not a set of enforced rules, then how is it binding?
The normative existence of law comes from the political acceptance of states (historically and now) that international law exists and is binding on them.
“All normal governments employ experts to provide routine and other advice on matters of international law and constantly define their relations with other states in terms of international law. Governments and their officials routinely use rules which they have for a very long time called the ‘law of nations’ or ‘international law’. It is not the case that the resort to law is propagandist - though it sometimes is. The evidence is that reference to international law has been a normal part of the process of decision-making.”
Brownlie I., ‘The Reality and Efficacy of International Law’, 1981 LII British Yearbook of International Law 1.
In other words, government officials, officials of international organisations and diplomats all refer to international law as a matter of routine when conducting international relations with one another.
It is true to say that international law is occasionally breached, and on occasion, that breach can be serious, and it may not be possible to bring that breach to an end. Nevertheless, in the words of Professor Louis Henkin: “Almost all nations observe almost all principles of international law and almost all of their obligations almost all of the time.”
Henkin L., ‘How Nations Behave’, Columbia University Press, 1979.
One of the key enforcement mechanisms is reciprocity. This is most apparent about the law of diplomatic privileges and immunities about which most states are both rending and receiving states. According to Professor Eileen Denza, the foremost authority on diplomatic law:
Reciprocity is itself “a constant and effective sanction for the observance of nearly all the rules of [diplomatic law] … Every state is both a sending and receiving state. Its representatives abroad are in some sense always hostages. Even on minor matters of privilege and protocol, their treatment may be based on reciprocity. For the most part, failure to accord privileges or immunities to diplomatic missions or their members is immediately apparent and is likely to be met by appropriate countermeasures.
Denza, E., ‘Diplomatic Law’, 4th Edn, OUP, 2016, p. 2.
The starting point for an understanding of what are the sources of international law is Article 38(1) of the Statute of the International Court of Justice 1945, which states as follows:
The Court, whose function is to decide by international law such disputes as are submitted to it, shall apply:
a) international conventions, whether general or particular, establishing rules expressly recognized by the contesting states;
b) international custom, as evidence of a general practice accepted as law;
c) the general principles of law recognized by civilized nations;
d) subject to the provisions of Article 59, [i.e. that only the parties bound by the decision in any particular case,] judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.
Article 2(1)(a) of the Vienna Convention on the Law of Treaties 1969 defies a treaty as:
“an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation.”
Treaties can be known by a variety of names including conventions, agreements, arrangements and statutes – the key is that they are written agreements between states.
Treaties are consensual instruments - by signing and ratifying international treaties, states consent to be bound by the provisions contained therein as against the other states parties to the relevant treaty.
The controversy surrounding this controversial effect of consent. According to John Setear:
“If consent is the basis of treaties, then how can treaties purport to bind a nation that wishes to withdraw its consent? … [T]o argue that the law of treaties rests upon consent and not give effect to withdrawals of consent is to say that obligations at time A stem from valid consent, but remain in force at a later time B despite the withdrawal of the consent that sanctified the obligations in the first place.”
Setear, J., “An Iterative Perspective on Treaties: A Synthesis of International Relations Theory and International Law”, 37 Harvard International Law Journal 139 (1996)
But an alternative view is posited by Michael Byers:
“…the central point of the consent-based theories of international law is that a state, by consenting, binds itself to behave in a certain manner even if it subsequently changes its mind about the desirability of such behaviour.”
Byers, M., “Taking the Law Out of International Law: A Critique of the ‘Iterative Perspective’”, 38 Harvard International Law Journal 201 (1997)
Byers approach is more in line with the accepted view of the effect of consent as encapsulated in the Latin principle pacta sunt servanda, which is codified in Article 26 of the Vienna Convention on the Law of Treaties which reads as follows:
“Every treaty in force is binding upon the parties to it and must be performed by them in good faith.”
Treaties can be bilateral, exists between a small number of states, or be significantly more multilateral to the point that some are considered to be law-making treaties:
The existence of a considerable number of multilateral international treaties to which all or almost all states are parties (i.e. general or universal international treaties), and also extensive efforts in the field of codification of international law have led to a situation when international treaties become a direct method of changing, developing and creating new norms of general international law.
Tunkin, G.I., “Coexistence and General International Law”, Collected Courses of the Hague Academy of International Law (Volume 95, 1958)
The most significant international treaties are:
Vienna Convention on Diplomatic Relations 1961; and
Vienna Convention on Consular Relations 1963
The second primary source of international law is Customary International Law. It is based on state practice (what states do) and the idea that it is done out of a perceived obligation to do so (known as opinio jure sive necessitatis).
(a) State practice
State practice can take the form of physical acts and statements – normally it would be statements by high-ranking state officials, but diplomats will have a role to play in both drafting those statements and in explaining them.
Duration – traditionally state practice had to occur over a significant pe period now duration is regarded as being less important.
Generality - according to the International Court of Justice (ICJ) in the North Sea Continental Shelf Cases state practice should be “extensive and virtually uniform”. I.C.J. Reports 1969, p.3
In practice, most states are silent on most issues – this would normally be understood as acquiescence.
The practice of smaller, less politically important states is rarely analysed or considered unless they relate to a matter of particular importance for that state. See ICJ decision in the Nicaragua Case (Merits). I.C.J. Reports 1986, p. 14. Gives rise to questions about the dominance of international law development by Western states.
(b) Opinio Juris
Practice should be followed in the belief that there exists a legal obligation to follow it, but this gives rise to the so-called chronological paradox – i.e. what comes first, the practice of the legal obligation.
Source of great discussion and debate between international law scholars. Important thing is to review what the states are doing or saying and what is their motivation for doing so.
Gives rise to questions about how to change international law. If a rule already exists because there is an obligation to comply, how can it be changed? My view is that there must be a breach oan f the existing rule that is then supported by other states until a new rule emerges, or fails to do so.
Once again, it is worth noting how this might favour the stronger, Western states.
(c) Overview of Customary International Law
The recently completed work of the International Law Commission on the topic of “The Identification of Customary International Law” (2018) led by Special Rapporteur Sir Michael Wood, provides a very useful overview of what customary international law is and how it is evidenced.
Subjects of International Law
States are the prime subjects of international law.
Four factors that point towards the primacy of States in international law:
International law is primarily a system of law between States - it is States which create international law through consent;
The ICJ is open in its contentious jurisdiction only to States - ICJ Statute, Art 34;
If an individual suffers abroad, the individual cannot bring a claim against the State in which he was harmed- it must be brought by his national State;
When a State pursues such a claim, it is not acting as an agent of the individual - in other words, it is pursuing its claim, not that of the individual (Civilian War Claimants Association v The King  AC 14 (HL)).
The traditional definition of a State is to be found in Article 1 of the Montevideo Convention 1933:
“The state as a person of international law should possess the following qualifications: (a) a permanent population; (b) a defined territory; (c) a government; and (d) a capacity to enter into relations with other states” Montevideo Convention 1933
Other subjects of international law include:
(b) International Organisations
Many international organisations have international legal personalities. This was confirmed for the United Nations in the ICJ case of Reparation for Injuries Suffered in the Service of the United Nations (the Reparations Case) (1949) ICJ Rep 174 in which the Court stated that:
The Court’s opinion is that fifty States, representing the vast majority of the international community, had the power, in conformity with international law, to bring into being an entity possessing objective international personality and not merely personality recognised by them alone, together with the capacity to bring international claims.
Other international organisations can have an inteinternationalal personality based on their constituent documents insofar as they indicate:
(1) an ability to contract, (2) an ability to sue and be sued, (3) an ability to own property, and (4) a volente distinctive - in other words, a capacity to make decisions which bind the membership, perhaps even when not all of the members have favoured the decision concerned.
The traditional view of the legal personality of individuals in international law is that they were objects as opposed to subjects of international law. Insofar as they could have legal personality, that personality was derivative insofar as it derived from the personality of the state.
So long … as the international community is composed of states, it is only through an exercise of their will, as expressed through treaty or agreement or as laid down by an international authority deriving its power from states, that a rule of law becomes binding upon an individual.
Jessup, Philip C., A Modern Law of Nations: An Introduction, (1949)
However, developments in international law, such as about human rights and international criminal law have ensured that it is increasingly necessary to consider individuals as direct recipients of rights and obligations in international law, with the [limited] capacity to enforce those rights.
For example, according to the Nuremberg and Tokyo International Military Tribunals (1946; 1948):
“International law imposes duties and liabilities upon individuals as well as upon states. crimes against international law are committed by men, not by abstract entities, and only by punishing individuals who commit such crimes can the provisions of international law be enforced”.
One of the clearest statements of individuals as participants in the international legal process is provided by HE Dame Rosalyn Higgins who has stated that:
“[T]opics such as the minimum treatment of aliens, requirements as to the conduct of hostilities and human rights are not simply exceptions conceded by historical chance within a system of rules that operates as between States. Rather, they are simply part and parcel of the fabric of international law, representing the claims that are naturally made by individual participants in contradistinction to state-participants.”
Nevertheless, Higgins has noted the lack of procedural capacity that individuals have:
“whatever view one takes on the somewhat philosophical matters we have been discussing, individuals are extremely handicapped in international law from the procedural point of view.”
Higgins, op cit, p.50