In the Supreme Court of Canada's 1993 judgment in Hunt v. T & N Plc, Justice La Forest laid down the following goal to international law : develop (
) co-ordination in the face of [the] diversity of the international system. In other words, international law has to reconcile the protection of diverse state interests and sovereignty with the principle of normative unity. Otherwise, it would not be effective. If sovereignty were understood in too restrictive a sense, or to the contrary, if no respect was shown to their interest, there would be no way to compel states to abide by their promises.
Now, the very fact of laying down a goal to international law seems strange given the particular nature of international law. States being sovereign and independent, they can make the arrangements they like with each other with no regard for normative unity. Normative unity is the rule within states, where there is one law that is issued from top to bottom and applies universally to every citizen, but it is not the rule within an anarchic system such as the international system, where actors are not subordinate to any institution entitled to issue legislation from top to bottom.
[...] We also need to examine under which conditions such international rules can be followed. Sovereignty as a pre-existing basis for normative unity How sovereignty leads to normative unity As we have seen, the principle of sovereignty has given birth to a number of common rules, well-entrenched in international law: the principle of non-intervention, the principle of state immunity, the banning of aggression The facts that all states are equally sovereign and that these principles are preservative of this sovereignty has given them the statute of universal rules. [...]
[...] As I will show, even the limits international law imposes on states seek at preserving each and every state's sovereignty, and recent evolutions of international law do not question this matter of fact. First and foremost, one has to remember that the fundamental principles of international law uphold state sovereignty. The principle of legal equality between states, as defined by article 2 of the UN Charter, is the direct corollary of state sovereignty. As all states are legally endowed with sovereignty, they are all legally equal. [...]
[...] based on the sovereignty of states International law takes its roots in an anarchical society, whose main actors states are sovereign and independent. It regulates the relations between states without threatening their sovereignty. Furthermore, it does not derive from one single legislative, whose decrees would be “hierarchically” imposed on the international community, but from the consent of states themselves. Consequently, international law cannot be a “world challenging state sovereignty. This absence of a single international legislative is corollary to the basis of international law is the consent of states. [...]
[...] There is a perpetual tension between sovereignty and normative unity in international law. Sovereignty seems to imply states can do whatever they want. However, the fact all states are equally sovereign and all want their sovereignty to be respected, has led to a number of universally agreed-upon principles which limit the ability of states to do as they please. But if we do “without sovereignty” while trying to make the world more just, it might lead to less normative unity. [...]
[...] Contemporary international law would thus place boundaries on the will of states. The moral and technical difficulties of the implementation of rules of ius cogens However, such thesis is untenable. Indeed, the principle of non- intervention makes it almost impossible for states to legally intervene in the affairs of another state failing to meet the requirements of ius cogens within its own borders. Furthermore, states increasingly tend to distrust customary international law, in so far as the integration of a custom within international law derives from the practice of a large number of states rather than from their express agreement. [...]
using our reader.