In international law, customary law refers to the general practice of States and intergovernmental organizations that is generally recognized by all States and is legally binding.
The objective is to find evidence of state practice by using sources such as:
- Records of a state’s foreign relations and diplomatic practices, as set forth in official statements, diplomatic exchanges;
- A state’s domestic court decisions;
- A state’s internal legislation concerning its international obligations;
- Newspaper reports of actions taken by states, statements made by government spokesmen to Parliament, to the press, at international conferences; and
- In resolutions, declarations & legislative acts of intergovernmental organizations.