Has the Aristotelian principle of formal equality (“Treat like cases as like” [Nicomachean Ethics, V.3. 1131a10-b15]) a status in international law ?
The principle of ‘sovereign equality’ of States can be regarded as a ‘general principle of international law’ in the sense of Article 38(1) of the ICJ Statute.
Its content is not, however, identical to the principle of equality as applied in the domestic legal order. Indeed, from an international legal perspective, the principle of sovereign equality must be reconciled with the premise that the creation of international law rests on State consent and that States are in principle free to choose which international legal obligations they wish to assume.
It should be noted that no direct legal consequences can be derived from it for States to uptake certain climate change mitigation obligations. In this regard we adhere to the author’s statement in an article from the Max Planck Encyclopaedia of International Law: “some urgent problems – e.g. our common concern for the environment and the climate – cannot be resolved through reliance on the principle of sovereign equality. They can only be resolved cooperatively.” (Article included as Annex I to this advice).
However, there is a strong case for the principle to be applied as guiding principle in negotiations.
Like treaties and customary rules, ‘general principles of international law’ constitute a primary source of international law (Cf. Article 38(1) of the Statute of the International Court of Justice). General principles of international law are principles that are (1) common to a broad variety of national legal systems (such as the principle that no-one can be judge and party in the same case, …) and that (2) can be transposed to the international level. Even if they are of equal normative power as treaties and customary rules, general principles of international law are only used to fill lacunae in the normative framework. References to general principles as a source of international law are relatively rare in the case-law of the International Court of Justice (ICJ). The ICJ has acknowledged for instance that the principle to act in good faith is a general principle of international law, without, however, seeing this principle as a source of autonomous substantive obligations.
The principle of equality can clearly be considered as a principle of law common to a great number of national legal systems (it is also a recognized principle of law in the case-law of the Court of Justice of the EU). The principle decrees that comparable situations must be treated likewise, lest there be an objective reason for treating cases differently. It is less obvious, however, that the cited principle can be transposed as such to the international plane. Indeed, one should not ignore the fact that at the national level, the principle of equality primarily aims at ensuring that the legislator will treat his subjects (e.g. natural persons and undertakings) in an equal manner. At the international level, however there is no ‘central legislator’ and States are at the same time creators of international legal obligations and the main subjects of international legal rules.
There are good arguments to support the view that the ‘principle of sovereign equality of States’ is effectively a ‘general principle of international law.’ The principle of sovereign equality of States is enshrined in Article 2(1) of the UN Charter. The scope of the principle is elaborated upon in the UN General Assembly’s ‘Friendly Relations Declaration (UN GA Res. 2625 (XXV) 1970).
The principle of sovereign equality of States
All States enjoy sovereign equality. They have equal rights and duties and are equal members of the international community, notwithstanding differences of an economic, social, political or other nature.
In particular, sovereign equality includes the following elements:
(a) States are judicially equal;
(b) Each State enjoys the rights inherent in full sovereignty;
(c) Each State has the duty to respect the personality of other States;
(d) The territorial integrity and political independence of the State are inviolable;
(e) Each State has the right freely to choose and develop its political, social, economic and cultural systems;
(f) Each State has the duty to comply fully and in good faith with its international obligations and to live in peace with other States.
The principle that States shall fulfil in good faith the obligations assumed by them in accordance with the Charter-:
Every State has the duty to fulfil in good faith the obligations assumed by it in accordance with the Charter of the United Nations.
Every State has the duty to fulfil in good faith its obligations under the generally recognized principles and rules of international law.
Every State has the duty to fulfil in good faith its obligations under international agreements valid under the generally recognized principles and rules of international law.
According to the late Ian Brownlie, the principal corollaries of the sovereignty and equality of States are: (1) a jurisdiction, prima facie exclusive, over a territory and the permanent population living there; (2) a duty of non-intervention in the area of exclusive jurisdiction of other States, and; (3) the dependence of obligations arising from customary law and treaties on the consent of the obligor (I. Brownlie, Principles of Public International Law (OUP: 2008 (7th ed.), 289).
It nonetheless follows from the foregoing that the content of the ‘principle of sovereign equality’ of States is not identical to that of the ‘principle of equality’ in the domestic legal order. In particular, the principle must be read in conjunction with the essentially voluntary nature of binding international commitments. Indeed, States are in principle free to choose which treaty obligations they wish to assume. The mere fact that other States assume certain obligations under international law (whether obligations relating to the protection of the environment or, for instance, to the conduct of hostilities) does not as such oblige them to do the same. In a similar vein, States can escape to being bound by new rules of customary international law by ‘persistently objecting’ to these (emerging) rules from the outset (cf. the persistent objection of nuclear States against an international legal norm outlawing the possession/use of nuclear weapons). It is also interesting to note that the ‘unequal’ nature of the respective obligations of different parties to a treaty is not accepted as a ground of invalidity under the Vienna Convention on the Law of Treaties (see O. Corten and P. Klein (eds.), The Vienna Convention on the law of treaties: a commentary Vol. II (OUP) (2011) 1027). In short, the principle of sovereign equality cannot be construed as entailing that States will or should at all times be bound by the same international legal obligations.
Further information on the principle of sovereign equality can inter alia be found in the aforementioned article from the Max Planck Encyclopaedia of International Law. It may be noted that according to the author of the article, “some urgent problems – e.g. our common concern for the environment and the climate – cannot be resolved through reliance on the principle of sovereign equality. They can only be resolved cooperatively.” (§ 59).