Introduction

International law applies to issues that concern more than one state. Where national law is primarily concerned with the interaction between individuals and individuals and the state, international law is concerned with the interaction between states. Although international law is often associated with big issues, such as war crimes, fighting climate change and international agreements, the scope is actually much wider and international law apllies to a lot of different issues.

As a legal system international law is quite different than most national legal systems. For example, in international law there is no legislative or executive branch. It is mostly up to national states to implement and interpret the international law.

What is the history of international law?

The early origins of international law as we know it now can be found in the informal rules and common practices countries abided by when they were engaging in cross-country trade in the late Middle Ages, somewhere between the 15th and 16 century. These traditions, rules, practices and “ways of doing things” where necessary to ensure predictability in international relations. At the very start these rules were mostly based on religious considerations enforced by the Catholic Church.

What is natural law?

In this time normative ideas could be mostly traced back to natural law (jus naturale), a holistic set of ideas about natural and social life in the entire world. Natural law mostly applied to the relation between a person and the world around him. Next to natural law there was general law or jus gentium, the law between people. Jus gentium was concidered inferior to jus naturale and even seen as being derived from it.

Natural law was applied wherever there was no international legal structure yet. So it led to a lot of agreements and rules on mercantile, maritime and diplomatic issues. When colonialism had increased significantly, the Spanisch Francisco de Vitoria was the first to say that native populations of the 'New World' where part of the global society and should therefor fall under natural law as well. This meant that everyone had certain rights under natural law that should be protected. This was the first time people started to speak of a global society rather than domestic ones.

The actual birth of national law is often traced back to the Peace of Westphalia (1648) that brought an end to a long war. International order and structure by law were established in an otherwise unorderly Europe. Natural law was used to diminish the overall chaos: thinkers like John Locke (1632-1704), Thomas Hobbes (1588-1679) and the lawyer Jean Bodin (1530-1596) had already introduced the idea that there is one sovereign only accountable to God who can break laws at his own discretion, which was an important idea for our conceptions of sovereignty today.

What is the relation to war?

These ideas were later used as a basis for e.g. the Declaration of Paris, which set a legal limit on the capture of private property at sea and the Declaration of St. Petersburg which prohibited the use of explosive bullets. The early start of international law as we know it now is related to colonialism and war. After the First World War The League of Nations was installed by the US to maintain world peace. In 1928 the Treaty of Paris attempted, unsuccessfully, to outlaw war. True achievements of international law were made in the period after the Second World War. The reaction of the world to the crimes of the Nazis was an important precedent of what was to come.

What is the United Nations?

The League of Nations was replaced by the United Nations, which is based on Westphalian principles. By means of the Charter of the United Nations, maintaining peace became an international effort. The Security Council is responsible for enforcing these principles and allowed to use force if this is needed. The UN was highly involved with the worldwide decolonization process. The UN furthermore installed the International Court of Justice (ICJ), the IMF, the World Bank and the General Agreement on Tariffs and Trade (GATT). Furthermore, the UN expanded with ‘sister organizations’ such as the NATO (a response to soviet threat).

Participation in the UN is particularly high in European countries, which has a general trend towards strong unification. With institutions like the European Court of Justice and the European Commission. Another institution, the Council of Europe installed an important treaty: the European Convention of Human Rights (ECHR). All these treaties have led to a steady decrease in conflicts. Although recently there has been plenty of critique on the costs this bears to national sovereignty. The Brexit was a direct result of this dissatisfaction, but it is seen in most western countries that feel like they keep handing in power and money without getting anything back.

Other criticism focusses on the fact that international law is based on Western values and is therefore not including enough. Nowadays there is an increase in economic competition with big actors such as Russia, China, the US and Europe. Non-western powers such as Russia and China can't or won't rely on international law when they work with or against each other, because they have different values and interests. Russia, China, Brazil, India and South Africa are starting to come up with rivals to the traditional global institutions.

What is the structure of international law?

With the Peace of Westphalia the international society was first recognized. International law now apllies in situations where domestic law doesn't suffice. This can for example be when there are disputes between different national legal systems. The scope of international law is thereby determined by the inadequacy of national law. There are two ways in which issues can become of interest to more than one state: there can arrise colliding interests of two or more states in the issue, or than can be a treaty about the issue.

What is the international law of coexistence and cooperation?

The legal structure is a horizontal one, it is mainly concerned with the way in which sovereign states interact. At first glance, international law may seem to be a cause of friction towards the desire of state sovereignty. In practice, however, the aim of international law is to facilitate this sovereignty by preventing international turmoil. It should be noted that the aim of international law is not to achieve community goals, such as fairness, but rather to uphold the order on a global scale and to ensure stability. As such it enables states to peacefully pursue their separate goals and interests. In this process there is always law creation taking place to some extent. International law of coexistence or 'general international law' explains that states can life in consent with eachother without acting the exactly same. Only the necessary is codified, leaving room for states to grow on their own. Note that this is a goal of international law, but that this is not always how states experience it.

The international law of cooperation indicates that states need each other to reach their goals. When there are collective interests, treaties can be made to reach these goals. This sounds simple, but in a lot of cases states have certain goals but are not willing to put money or effort towards them (because they would benefit more from it if other states made it work and they can profit from the endresult). This is why binding agreements in the form of treaties is needed.

What is the basis of international obligation?

Two streams of thought can be distinguished: natural and positive law. Natural law is concentrated on the binding force of international law, the nature requires certain behavior, which should be enforced. At first glance, there seems to be an inherent clash within this theory between state sovereignty and accountability. However, as discussed earlier, positive constraints may actually increase freedom and therefore also sovereignty. In practice, states never truly question whether they are bound by international law. Positive law puts its focus on voluntary compliance.

What is the relationship between national and international law?

Although international law stands, by principle, above national law, there is a level of discretion as to how states comply with the international law. An exception to this rule is EU-law which generally leaves less discretion to its Member States. A state cannot defend itself by saying that compliance would negate the national law. In the application and enforcement of international law on a national level two legal theories are important: monism and dualism. Monism means that the national and international law form one coherent set of legal rules, whereas dualism states that they are separate systems. Following dualism, international law therefore needs to be transposed into national law to become enforceable. How this is done depends on a state’s constitution. Generally international law is incorporated in the national legal system, but it depends on the states constitution wheter this is necessary or not.

How is international law enforced?

A central issue is that there is no international police force to enforce international law. There are, however, several monitoring bodies: the CJEU and the ECtHR. These bodies are endowed to make binding decisions. Nevertheless actual enforcement can be problematic. One way to solve this problem is to take collective action, such as the sanctions in response to the annexation of the Crimea by Russia. Other tools can be cancelling state visits, halting state aid or to ban trade with a country. As a whole, the real enforcement tools on an international level are limited, nevertheless mostly because of reciprocity states rarely disobey the international law. Because all states are so intertwined with each other they now need each other. This is why states rarely disobey, because they can't handle the other states to cut the economic and diplomatic relations with them.

Is international law an inadequate tool in the 21st century?

On the other side of the trade-off between state sovereignty and international law there is the discussion of the adequacy of international law to achieve global goals such as combatting poverty, ensuring fairness and achieving ‘justice’. However, the international law was never established to reach these goals. It was introduced to ensure international order and stability. These considerations usually gain priority over goals of fairness or justice. Recent humanitarian interventions that happened without the aid of the UN imposed a serious threat to international peace. The ‘Westphalian way’ (where the state has a central role) of organizing the current international legal
system is of course not the only way to do things. Other ways could be to place ethnicity or religion in a more central role or even to install a global government. Overall, although the current system has its weaknesses there is some consensus that there currently is no better option.