The disastrous consequences of the recent aggressions against Iraq, Afghanistan, Syria, Yemen and Ukraine, to name just a few, show the urgent need to revive the principle of non-intervention into another state. This principle of international law includes, but is not limited to, the prohibition of the threat or use of force against the territorial integrity or political independence of any state, according to Article 2.4 of the Charter of the United Nations.
The Swiss legal philosopher Emmerich de Vattel is credited with being the first to formulate the principle of non-intervention in his Droit de gens ou principles de la loi naturelle (The Law of Nations) published in 1758. Essentially, the principle establishes the right of territorial sovereignty possessed by each nation. The scope of the principle, however, has been subject to debate.
For example, what constitutes intervention in practical terms? Does it include only the use or threat of military force, or it also includes economic sanctions, cyber warfare or other kinds of non-military intervention such as propaganda campaigns or control of media messages to other countries?
According to Michael Wood, a member of the UN International Law Commission, one of the earliest treaty formulations of the principle was included in the Article 15 (8) of the Covenant of the League of Nations and the Montevideo Convention on Rights and Duties of States of 1933, which precluded “interference with the freedom, the sovereignty or other internal affairs, or the processes of the Governments of other nations,” together with the Additional Protocol on Non-Intervention of 1936.
Later on, the UN General Assembly issued a Declaration on the Inadmissibility of Intervention and Interference in the Domestic Affairs of States (UNGA resolution 2131 (XX) 1965). According to Oppenheim’s International Law, the prohibition of intervention “is a corollary of every state’s right to sovereignty, territorial integrity and political independence.”
A paradigmatic case in which this principle was applied was that of Nicaragua vs. United States, following the U.S. support for the “contras” fighting the Nicaraguan Government and the mining of Nicaraguan harbors. The case was decided in 1986 by the International Court of Justice (ICJ).
The ICJ ruled in favor of Nicaragua and against the United States, and awarded reparations to the Nicaraguan Government. According to the ICJ, the actions of the U.S. against Nicaragua violated international law. The U.S. refused to participate in the proceedings after the Court rejected its argument that the ICJ lacked jurisdiction to hear the case.