1 Definition of international law
There are many definitions of international law. Their content depends on the time and context in which they were formulated, and the perspective from which international law was viewed, e.g. positivist, naturalist, feminist, sociological, or ethical. Nevertheless, Professor Shearer’s following definition encompasses the main features of international law:
International law may be defined as that body of law which is composed for its greater part of the principles and rules of conduct which states feel themselves bound to observe, and therefore, do commonly observe in their relations with each other, and which includes also:
- (a) the rules of law relating to the functioning of international institutions or organisations, their relations with each other, and their relations with states and individuals; and
- (b) certain rules of law relating to individuals and non-states so far as the rights or duties of such individuals and non-state entities are the concern of the international community.
2 A brief history of international law
A brief history of international law, beginning with ancient times, is relevant to the understanding of many rules and principles of international law.
A. From Ancient Times to the Middle Ages
The first recorded treaties concluded around 2100 BC between rulers of ancient Eastern Mediterranean States were based on the principle of pacta sunt servanda (i.e. agreements must be kept) and the principle of good faith. Both principles were recognised by the 1969 Vienna Convention of the Law of Treaties (VCLT) as being fundamental principles of the modern law of treaties (see Chapter 3).
Ancient Greece’s contribution to the development of international law was the establishment of a highly sophisticated system of international arbitration and the institution of proxeny (State hospitality) which is at the root of consular protection of foreigners. Further, certain rules of conduct of wars aimed at restricting the worst atrocities developed between ancient Greek city States, e.g. if a city was captured, those who had taken refuge in a temple were to be spared, and prisoners were to be ransomed or exchanged, or at worst to be enslaved but not killed,
Imperial Rome’s contribution was the development of:
- ■ jus fetiale, consisting of religious rules, which governed Rome’s external relations and formal declarations of war which, inter alia, recognised the inviolability of ambassadors, and was at the origin of the distinction between ‘just’ and ‘unjust’ war;
- ■ jus gentium, which governed relations between Roman citizens and foreigners. It became an essential part of Roman law and thus greatly influenced all European legal systems and, through them, public international law;
- ■ the doctrine of ‘just’ war by Cicero;
- ■ the doctrine of the universal law of nature known as ‘natural law’.
B. The Middle Ages
In the Middle Ages two sets of truly international rules developed, one being the lex mercatoria which consisted of rules of conduct and fair dealing between merchants and the other being maritime customary law. The doctrine of ‘just’ and ‘unjust’ war was further developed by St Augustine of Hippo, and later refined by St Thomas Aquinas (see Chapter 15.2.2), and the first attempts were made at restraining the methods and means of warfare and maintaining peace through the institution of the Peace of God (see Chapters 15.2.2. and 17.3).
C. From the 1648 Peace Treaty of Westphalia to the 1815 Congress of Vienna
The period from the 1648 Peace Treaty of Westphalia to the 1815 Congress of Vienna is considered as the period of formation of ‘classical’ international law. The 1648 Treaty of Westphalia, which is often referred to as the constitutional treaty of Europe, recognised the principles of sovereignty, territorial integrity and the equality of States. It legitimised the principle of non-interference in the affairs of a State and recognised that a State was independent of the Church. Further, the Treaty established a system of balance of power, which lasted until the French Revolution and the Napoleonic Wars, and was aimed at preventing wars.
The intellectual support for new ideas was provided by scholars, in particular the Anglo-Dutch School represented by Hugo Grotius and Alberto Gentilli.
At the end of the eighteenth century, the enlightenment ideals supporting the aspirations of the British colonies in North America which were fighting for independence from the British Monarchy, and supporting the French people fighting against France’s monarchist tyranny, feudal aristocratic privileges and the Catholic clergy had great influence on the development of human rights (see Chapter 12.1) and the principle of self-determination (see Chapter 13).
D. From the 1815 Congress of Vienna to the outbreak of WWI in 1914
The 1815 Congress of Vienna codified the law on diplomatic agents and missions, prohibited slave trading and laid the foundations for the free navigation of rivers which flow through at least two European States. At the Congress the five powers (The UK, Austria, Prussia and Russia who were joined by France in1818) promised to meet periodically over the next 20 years to discuss common problems and to co-operate on major issues to prevent war. The main objective of the Congress was to achieve a new balance of powers in Europe which would guarantee stability, peace and the status quo in Europe. In order to achieve this, territorial arrangements were made to ensure that no European State would be more powerful than any other and therefore no State would be able to build an empire similar to that built by Napoleon. The restoration of legitimate rulers and the prevention of political revolutions, similar to the 1789 French revolution, supported the new system of balance of powers. The so-called Concert of Europe which developed out of the Congress of Vienna was mostly successful in preserving peace in Europe for almost a century. It constituted the first serious attempt in modern times to establish an international mechanism to maintain peace. The system of periodic meetings also began a new diplomatic era in Europe which was marked by the adoption of numerous multilateral treaties.
The main features of international law during the period 1815–1914 were as follows:
- ■ the unorganised character of the international community, which was composed of a multitude of sovereign States legally equal;
- ■ the acceptance of war as the ultimate instrument of enforcing law and safeguarding national honour and interests;
- ■ the recognition of States as the only subjects of international law.
The nineteenth century was the century of positivism which was enunciated by the French philosopher Auguste Compte. The foundations of positivism in law were laid down by John Austin and Jeremy Bentham.
The second half of the nineteenth century saw the emergence of international organisations, e.g. the International Committee of the Red Cross in the 1860s and the Universal Postal Union in 1874.
3 The nature of international law
The status of international law as ‘law’ has been challenged at both the theoretical level (by John Austin (1790–1859) and by H.L.A. Hart (1907–1992), and at the practical level. The main argument against the existence of international law as ‘law’ is that international law does not have any legislature, judiciary or executive within the usual understanding of these terms, responsible for creation, interpretation and enforcement of that law.
The most convincing arguments in favour of the existence of international law as law are that States recognise and observe international law (with the consequence that there is substantial order in international relations) and that international law is practised on a daily basis by international lawyers, intergovernmental organisations (IGOs) and other non-State actors, and applied by domestic and international courts.
4 Enforcement of international law
Methods of enforcement of international law differ from those available under municipal law because international law does not have all the attributes of municipal law i.e. there is no legislature, judiciary or executive. However, the fact that international law has no centralised process of enforcement does not mean that international law is not obeyed. A State obeys international law because:
- ■ the prospective long term advantage of compliance prevails over any short term advantage resulting from violation of international law;
- ■ it wants to maintain its good Reputation; it fears Retaliatory measures or measures based on Reciprocity that may be taken by a victim State (‘the three Rs compliance’);
- ■ the United Nations Security Council (UNSC) may take various measures, including the use of force, under Chapter VII of the UN Charter to force a State to comply with international law;
- ■ it is bound under many international treaties to accept the compulsory jurisdiction and the judgments of a body established by treaty to deal with disputes arising out of it;
- ■ it fears public opinion both at home and abroad.
Enforcement of international criminal law against individuals is ensured by the International Criminal Court (ICC) which has jurisdiction to prosecute and punish individuals responsible for the most serious violations of human rights law (HRL) and international humanitarian law (IHL) as well as by other international criminal courts, by States, and by individuals who may bring criminal or civil actions in national courts against foreign persons who have violated international law.