International law is a complex of rules and principles that govern relations between states. These laws may be based on international treaties, custom and state practice, or judicial decisions.

International relations have tended to be conducted by diplomatic means, but international disputes sometimes escalate into war. Nonetheless, international law has developed principles to guide the conduct of hostilities and to protect civilians during conflicts.

This body of law includes rules governing international crime, civil rights, international trade, and environmental issues such as climate change, outer space, global communications and international waters. In addition, it regulates the treatment of prisoners and issues pertaining to refugees and migration.

In addition to defining legal responsibilities of states, international law sets out a common conceptual language and methods for settling disputes peacefully. This is done through negotiations, mediation, conciliation, arbitration or adjudication.

Another important component of international law is the protection of human rights. In addition to providing a framework for the conduct of international relations, international law also provides redress to victims of violations by other nations.

For example, if a foreign government tortures an American citizen, that person can file a complaint with the home state or seek redress in international courts.

Although the traditional conception of international law was largely confined to sovereign states and the Holy See, recent interpretations have included corporations and even individuals. In fact, the subject of international law has shifted considerably from the classical concerns of war, peace and diplomacy to include human rights, economic and trade issues, space law and international organizations.