Military Self-Defence against International Terrorism

Summary of Ove Bring's article in RSAWSPJ no 6 2001.

Before 11th September 2001, Article 51 of the Charter of the United Nations on individual or collective self-defence was generally interpreted in a restrictive fashion. Most states (with the exception of the United States and Israel) did not recognize a right of self-defence against terrorist networks hiding in territories of other states; nor did a majority of states recognize the legitimacy of military action intended to prevent future attacks. Self-defence was seen as an action of immediate response to an ongoing armed attack. Preventive or anticipatory self-defence was more or less ruled out.

The terrorist attacks against the World Trade Center and the Pentagon created a political will to adapt the concept of self-defence to a new threat - the threat of large-scale terrorist attacks against nations as such. For traditional self-defence scenarios, the restrictive interpretation of Article 51 would still be valid, but in defence of "open societies" against the new threat there was a widespread feeling among political decision-makers that preventive military action should no longer be ruled out.

Through a process of State practice between 12th September and 10th October - which included UN Security Council Resolutions, NATO Declarations, supportive statements by the European Union, and a declaration by the Organization of Islamic States - the traditional rule of self-defence was amended and extended. Particularly important was the meeting of the UN Security Council on 8th October, although no resolution was adopted at that time. The Council had met to receive information on and discuss the US-UK bombings of targets in Afghanistan which had started on the preceding day. In a statement by the President of the Council, it was underlined that the military action had been reported to the Council as measures of self-defence (in accordance with the requirement of Article 51 that actions in self-defence should be so reported). “The members of the Council were appreciative of the presentation made by the United States and the United Kingdom.” No member of the Council, the most important body of the international community, objected to the new interpretation of Article 51. Legitimacy was established (an unwritten Article 51 1/2).

The matter of proportionality as a restrictive principle in the context of self-defence is not discussed above, but it should be noted that the principle in question could imply a time limit, after which it is no longer "reasonable" or "proportional" to continue military operations which result in increased sufferings of the civilian population.