Internationaal recht – Nicaragua

Facts

The US government tried to overthrow the (left) regime that had settled in Nicaragua. The US provided support for the rebel movement in Nicaragua, through the laying of mines in territorial waters of that state. However, Nicaragua, claims that the actions of the US were contrary to some rules of customary law, such as the prohibition of intervention in the domestic affairs of another state and the ban on violent action against another state.

Question before the Court:

Are the actions of the USA in conflict with customary law? Can the USA be held liable for violations of international law committed by the insurgents?

International Court of Justice

As far as conflicts with customary law are concerned, it must first be established whether rules of customary law and prohibition of the use of force existed in customary law.
The Court concludes that states still consider violations of these prohibitions to be unlawful. In addition, the Court considers that the existence of a rule of customary law can be confirmed by the way the states justify their own behaviour. If states that are accused of violating a customary rule defend their behaviour as an exception to an existing customary rule, they indicate that they accept the existence of the rule. The Court therefore holds that the actions of the United States are contrary to customary international law.

As far as US state liability is concerned, the extent to which the state controls the acts of the insurgents is of great importance. The Court ruled that the US cannot be held liable for violations of international law committed by the insurgents. Although they were heavily dependent on US support, it was not proven that this state had effective control over the explicit operations.