Implementation of International Law at the Domestic Level
Some rules of international law must be applied within the state. For example, customary rules grant privileges and immunities to diplomatic agents, provided they are foreigners. These rules must be implemented by the courts, judicial or administrative authorities, or the executive branch of a state and must be applied to diplomats accredited to that state. One example is that the state is a party to granting commercial or customs rights to citizens of another country. These rights must also be applied by courts and administrative authorities. However, to facilitate the implementation of international legal norms, it is appropriate to introduce them in some form within the domestic legal system. In some cases, international law itself demands this introduction. How can this introduction or incorporation of international standards into domestic law be achieved?
International law does not impose a specific method on states to introduce its rules internally. It only requires them to ensure compliance with the rules of international law. Thus, it corresponds to each state to establish the modalities of reception in its constitution and its laws, as well as in judicial and administrative practices.
Methods
A) Reception of Customary Law
- A state can incorporate certain rules of customary international law into its domestic legal order by enacting laws that reproduce the contents of such rules. For example, a state can enact a law that grants foreign diplomatic envoys accredited to the country certain privileges and immunities accorded to them under customary international law. What does this law do? In this first case, the law spells out each privilege and immunity one by one and outlines their conditions of application. Then, when courts apply this law, they will be applying their own law, i.e., domestic law.
- Reception can also be done through a statutory provision. This law refers to certain rules of customary international law, making them applicable in domestic law. For example, in the same case mentioned earlier, the internal law simply states that foreign diplomatic agents will enjoy in the country the privileges and immunities granted to them by international law. In this case, the domestic law “makes a referral to international law,” as it is known in the jargon of international law. It is then up to the courts to determine the rules of international law applicable to diplomatic agents.
- Some states have what is known as a global reception of customary international law in their domestic law, allowing it to be applied by the courts and national administrative authorities when the occasion arises. In some cases, the overall reception is performed by means of an express constitutional provision. For example, the German constitution states that the general rules of international law are an integral part of German law and take precedence over domestic laws, directly creating rights and obligations for the inhabitants of German territory. This provision not only incorporates general international law into German law but also gives it primacy over the latter. In England, there is no such provision, but the Law Commission believes that all rules of customary international law that are universally recognized and have received the assent of the country are, per se, part of domestic law. However, this doctrine of incorporation in the English case has a major limitation because it indicates that an Act of Parliament prevails over the rules of customary international law and must be applied by courts in all cases without checking their conformity with international law. In Chile, both the courts and legal scholars have recognized that international law, in general, forms part of domestic law. In fact, Andrés Bello wrote in his Principles of International Law in 1831 that no nation should deny the right of individuals to be part of the country. A few years later, the Minister of Foreign Affairs stated in a letter to the Chargé d’Affaires of Chile in France that the common law of nations is a law of the Republic in all matters where particular laws or conventions with foreign powers have not repealed it, particularly our political constitution, which establishes the precedence of general international law, particularly on human rights, over domestic rules.
An important consequence of customary international law being part of national law is that it is not necessary for the parties to actually prove it in court, as they must do with foreign law.