International law is a collection of rules that govern the relations between states. This classic definition, developed by Jeremy Bentham, did not include individuals or international organizations, two key actors in modern international law. International law provides normative guidelines, methods, and mechanisms for international actors. Traditionally, international law has dealt with questions of diplomacy, war, and peace. International law defines the legal responsibilities of states in their conduct with one another and provides a framework for the treatment of individuals within states.

States can enter into formal agreements with other states to establish obligations under international law. Treaties are signed, ratified, and entered into force and serve as legally binding agreements. The basic principle that agreements must be kept, pacta sunt servanda, illustrates the concept that ...