Customary international law recognises the existence of certain requirements that must be met before a state can validly espouse its national's interest. The two main requirements are exhaustion of local remedies and continuous nationality.

The diplomatic protection is available to individuals located in a foreign state which has obligations in different fields of life, including trade, sailing, commerce, and protection of human rights or property rights. These obliga-tions can derive from international treaties, customary international law or gen-eral principles of law.

According to the International Law Commission, diplomatic protection consists of the invocation by a State, through diplomatic action or other means of peaceful settlement, of the responsibility of another State for an injury caused by an internationally wrongful act of that State to a natural or legal person that is a national of the former State with a view to the implementation of such responsibility.