How to Differentiate Between International Law and National Law

International law, a term introduced by philosopher Jeremy Bentham around the year 1800, refers to a system of rulings, principles, and customs designed to regulate interactions between countries (examples include human rights, military intervention, and global issues like climate change). In contrast, national law governs the actions of individuals and entities within the borders of a sovereign state (for example, civil and criminal law).

Understand the concept of international public law. When disputes and conflicts arise between sovereign states, they are resolved according to the principles of international public law. This legal system includes treaties and rulings that interpret those treaties.

• International law acknowledges that all sovereign states are equal before the law.
• Conflicts under international public law can be settled either through diplomatic negotiations or by the International Court of Justice. This court is part of the United Nations, and fifteen judges are elected by the UN General Assembly to use international legal precedents in resolving legal disputes between governments.
• The International Court of Justice has jurisdiction in two cases: first, when both countries agree to submit a dispute to the court, and second, when a treaty designates the court as the authority for resolving disputes.

Distinguishing International Private Law from Public International Law. When citizens of different states are involved in legal disputes, the question often arises about which law should be applied. The issue of choosing applicable law in civil matters, ranging from contract law to family law, has been discussed at the Hague Conference on Private International Law.

• Generally, the court will first look at the terms of the contract to determine which court has jurisdiction. If the contract does not specify the language of the proceedings, the court will consider the overall context of the contract, the actions of the parties during its formation (known as commitment evidence), and whether the parties can agree on a jurisdiction.

Review the sources of international law. Customary international law is codified in the Vienna Convention on the Law of Treaties. According to this customary law, states agree to follow certain practices regarding legal obligations.

Define municipal law. In common usage, especially in the United States, the term municipal refers to a city or town. However, in the context of international law, 'municipal' refers to any sovereign entity, including a nation, state, county, province, city, or town. Essentially, municipal law refers to the internal laws of a government.

Learn the basics of national law. National law (or domestic law) has two main forms. First, civil law, which consists of written laws and regulations for the enforcement of those written laws. Statutes are passed by state legislative bodies or through popular vote. National law is also made up of common law, which is created by both lower and higher courts within a country.

• Common types of national law include criminal law, traffic laws, and government regulations. In essence, national law governs the relationship between citizens and their government.

Understand the enforcement mechanisms of national law. Civil law and common law are implemented in distinct ways. For example, law enforcement bodies, from local police to federal investigators, hold the power to enforce both criminal and civil laws. On the other hand, common law, often called judge-made law, mainly comes into play when addressing legal issues like contract law or disputes between domestic companies.

Examine how laws are made. There is no global legislative body. The United Nations agrees on conventions that member countries decide to ratify and follow, but there is no international governing entity. International law is formed through treaties, customs, and agreements between countries, which stands in stark contrast to the legislative processes of national law creation.

• International treaties are binding legal agreements between countries. In a nation like the United States, a treaty is an agreement approved by Congress. Once ratified, the treaty holds the same legal weight as federal law (meaning it functions like a statute). As a result, treaties can have different meanings depending on the country or international body discussing them. For instance, the Treaty of Versailles is a peace agreement signed after World War I.
• International agreements tend to be less formal than treaties, although the international community considers them on equal footing with treaties. In the U.S., international agreements do not require Congressional approval, and they are only applicable within national law (meaning they can't be enforced as separate laws). A notable example of an international agreement is the Kyoto Protocol, which aims to cut global emissions to combat climate change.
• International customary law arises when a nation consistently and consciously follows certain practices because it believes it has a legal obligation to do so. Customary law is not necessarily written down and is the least formal form of international law.

Study how laws are enforced. No police agency has complete international jurisdiction. Even INTERPOL, which has 190 member countries, only serves as a coordinating body that provides information and training to national police forces. When disputes arise between nations, international law is enforced through treaties, United Nations conventions, and the International Court of Justice.

• In legal disputes governed by national law, the case is decided based on civil law in the form of statutes or under the common law system of the state in which the case arises.

Learn about the participants and their impact. If the two parties involved in a legal dispute are sovereign nations, international law, international enforcement methods, and dispute resolution processes will apply. Conversely, if both parties are citizens of the same country, national law enforcement agencies, court systems, and internal judicial principles will be used to settle the dispute.

• When a dispute occurs between individuals from different countries or between an individual and the government of another nation, the court will refer to treaties, United Nations conventions, or contracts to gather jurisdictional information before addressing the dispute.

Analyze the relationship from the perspective of the "dualism" theory. Many in the international community view international law and national law as two separate entities. They argue that each system governs distinct matters and exists in its own domain. According to their view, international law regulates the behavior of states and their interactions with each other. Conversely, national law is seen as governing the behavior of individuals living within a sovereign state.

• If you subscribe to the dualism theory, you would assert that these two systems hardly interact. However, if there is interaction, it occurs when national law acknowledges and incorporates international legal principles. Therefore, national law takes precedence over international law. In the event of a conflict between the two, national courts will apply national law.

Analyze the relationship from the perspective of the "monism" theory. Monists believe that both international law and national law are part of a unified legal system. For them, both systems are based on the same foundation to regulate human conduct and material matters.

• If you align with the monism theory, you would argue that international law takes precedence over national law, even within national courts.

To what extent must countries comply with international law? While countries have a general obligation to adhere to international law, there is often a significant variation in how they comply. In general, nations are free to decide how to integrate international law into their domestic legal systems. They handle this issue in various ways, but the prevailing trend follows the dualism theory. Consequently, most nations formally integrate international law by passing domestic legislation.

Assess the impact of international law on national law. In the international arena, international law prevails over national law. However, national law serves as valuable evidence of international customary law and general legal principles. Furthermore, international law often leaves questions that only national law can answer. Thus, when appearing before an international court, national law can be used to determine whether international law has been violated. In fact, international courts may refer to national law to help interpret international law.

• In the domestic context (within a country), the interaction between the two legal systems is more difficult to assess. Generally, informal international agreements and customs will be acknowledged and followed, as long as they do not conflict with national law. In case of a conflict, national law is typically given priority. However, formal treaties are often considered to hold the same value as national law, provided they can be self-executing (meaning they function within the territory of a nation). Some countries may have a different view on this issue.