International law

Many lands have rules.

These rules help them get along. They help keep peace.

People use them to talk and trade. A man named Hugo Grotius wrote about rules. He thought laws could help states live in peace. These rules can cover many things. They can cover war or how to treat people. They also help with money and trade. Using rules helps the world stay fair.

It is good to have rules for everyone.

International law is a set of rules for the world.

These rules help countries work together. They help with trade and diplomacy. They also cover human rights.

Rules are written down. Norms are unwritten guides for how to act.

Countries make these rules through treaties. A treaty is a formal agreement. They also use customs. Customs are common ways of acting. There is no single leader to enforce these laws. Instead, countries must agree to follow them. If a country breaks a rule, others may act. They might use diplomacy or economic sanctions. Sanctions are ways to pressure a country with money.

History shows us these rules are very old. Long ago, city-states made peace treaties. One famous treaty was the Treaty of Kadesh.

In the past, the Romans had laws for foreigners. Later, thinkers like Hugo Grotius helped shape modern laws. He believed laws could help nations live in peace. Today, groups like the European Union use supranational law. This means nations share some power to make rules.

International law is a special set of rules for the world.

These rules help states and other groups know how to act. They cover many areas like diplomacy, trade, and human rights. Rules are usually written down as formal expectations. Norms are different because they are unwritten guidelines. They come from long-standing customs and social practices. This system helps different actors interact with each other.

How does this system work without one single leader? Unlike laws in a single country, international law relies on consent. This means states must agree to follow the rules. There is no global authority to force everyone to obey. If a state breaks a treaty, others might respond. They might use diplomacy to talk about the problem. They could also use economic sanctions to apply pressure. In some cases, it may even lead to war.

People have been making agreements for a very long time.

In ancient times, the city-states of Lagash and Umma made a peace treaty around 3100 BCE. Later, in 1279 BCE, an Egyptian pharaoh and a Hittite king made an agreement. The Roman Empire also used a framework called jus gentium. This helped govern how foreigners lived within Rome. In China, rules for diplomacy emerged during the eighth century BCE. Different schools of thought helped guide these foreign relations.

Many thinkers helped shape the modern ideas we use today.

Jeremy Bentham coined the term "international law" in 1789. Hugo Grotius is often called the father of international law. In 1625, he wrote a famous book about how nations should act. Francisco de Vitoria also worked on ideas about the rights of people. He is seen as an originator of modern international law. Lassa Oppenheim later gave a definition that many scholars still use today.

Today, international law connects to the laws in your own country. Sometimes, a national law can become international law through a treaty. For example, the Geneva Conventions require national laws to follow certain rules. Some groups even use supranational law to make decisions together. The European Union is a common example of this system. In these systems, nations give up some power to a shared group. This helps different countries work as one large team.

International law, often called public international law or the law of nations, is a framework of rules and standards. These rules govern the mutual relations between states and other international actors. Actors include individuals, states, international organizations, and non-state groups. These entities make behavioral choices that can be lawful or unlawful. The system establishes norms across many domains, such as diplomacy, war, economic relations, and human rights.

To understand this system, one must distinguish between rules and norms. Rules are formal, written expectations that outline required behavior. Norms are informal, unwritten guidelines shaped by custom and social practice. International law operates differently than domestic legal systems because it relies largely on consent. There is no universally accepted global authority to enforce laws upon sovereign states. Because of this, states may choose to breach a treaty or ignore a norm. Such violations can result in disapproval, economic sanctions, diplomacy, or even war.

There are several distinct types of international legal frameworks. Public international law covers rules with an international origin. In contrast, private international law deals with whether national courts have jurisdiction over foreign cases. Some scholars use the term transnational law to describe rules that transcend national frontiers. Another concept is supranational law, which is a relatively new political term. In a supranational system, nations explicitly cede decision-making power to a shared judiciary and legislature. The European Union serves as the most common example of this integrated system.

History shows that states have negotiated agreements since antiquity. One of the earliest recorded examples is a peace treaty between Mesopotamian city-states around 3100 BCE. Another significant agreement occurred in 1279 BCE between Pharaoh Ramesses II and Hittite King Ḫattušili III.

The Roman Empire established the concept of *jus gentium*. This framework governed the status of foreigners living in Rome. In China, rules for diplomacy and treaty-making emerged during the eighth century BCE. During the Warring States period, Confucianism and Legalism provided different principles to guide foreign relations.

During the Middle Ages, various specialized legal systems emerged to provide stability. In Europe, *lex mercatoria*, or merchant law, regulated trade and commerce. Maritime codes like the Rolls of Oléron regulated shipping in North-western Europe. In the Islamic world, Muhammad al-Shaybani published *Al-Siyar Al-Kabīr* in the eighth century. This work governed foreign relations by dividing the world into different legal categories. These Islamic principles regarding military conduct acted as precursors to modern international humanitarian law.

The Renaissance brought the emergence of modern international law through key thinkers. Francisco de Vitoria is often called the originator of modern international law for his work on sovereign equality. In 1625, the Dutch jurist Hugo Grotius published *De Jure Belli ac Pacis*. Grotius is widely regarded as the father of international law because he envisioned a society of states governed by law rather than force.

Later, Jeremy Bentham coined the specific term "international law" in his 1789 book. Lassa Oppenheim provided a definition based on the common consent of sovereign and equal states.

International law is deeply connected to national legal systems. National law can become international law when treaties permit jurisdiction for supranational tribunals. For instance, the Geneva Conventions require national laws to conform to specific treaty provisions. This connection allows international obligations to be integrated into domestic law through national constitutions. The relationship remains complex, as states can interpret international law in ways they see fit. This can lead to significant local effects when different interpretations are applied.