What is International Law?
International law can be defined as “the collection of treaties, customs, and multilateral agreements governing the interaction of nations and multinational businesses or nongovernmental organizations.”
The primary subjects of international law are states (countries). States are the creators of international law and the ones who determine whether to accept the laws or not. The major sources of international law are customary international law and conventional law, which can come in different forms, such as treaties. Customary international law develops when many states follow certain customs generally and consistently for a particular period of time; eventually, it is considered to be “law” because so many states follow it. There are also many different types of international agreements. For instance, bilateral treaties are international agreements between two states. The states that take part in a treaty are the ones that are bound by it; other states are not.
There are often questions about whether international law is law and whether it is legitimate. These questions arise because in international law, unlike in domestic law, there is no international governing body or police force that can force states to comply with international laws. In other words, complying with international law is often voluntary for states rather than required.
Some states consider international law to be superior to their domestic law, so if one law conflicts with the other they will choose to follow the international law. These states are under international law. The United States, on the other hand, “is not a ‘state’ under international law, since the Constitution does not vest it with a capacity to conduct foreign relations.” “This means that the United States is not restricted from making laws governing its own territory, and international law is a part of the law of the United States only for the application of its principles on questions of international rights and duties.”
International organizations play a large role in international law. They are usually created by international agreements. Even though the resolutions that international organizations pass are not required to be adhered to, in many instances, states comply with them. For instance, The United Nations (UN), the most influential international organization, is adhered to by most states, even non-members. The purposes of the UN are to “maintain peace and security, to develop friendly relations among nations, to achieve international cooperation in solving international problems, and to be a center for harmonizing the actions of the nations and attaining their common ends.” The International Court of Justice was established by the UN Charter.
Although international judicial courts exist, their jurisdiction is often limited. For instance, even for the ICJ, states have to consent to its jurisdiction. There are also very few international judicial courts, generally.
Finally, international law is often interpreted many different ways by different states even when they follow the laws. For instance, the ICCPR prohibits torture, but different states interpret what is considered to be torture differently. The United States, for instance, has a higher threshold for torture.