An der Nahtstelle der Friedensordnung – Bedeutung und Grenzen des Selbstverteidigungsrechts im System kollektiver Sicherheit

The past decade has provided ample reason for the academic debate to focus on the inherent conditions of the right of self-defence. However, it is also the role and function of this right within the system of the UN-Charter which raises important questions. They are the actual subject-matter of Article 51 of the Charter which complements the inherent limits of self-defence with a set of system-related limits. The conceptual interrelation between self-defence and collective security is ambiguous. On the one hand, the system of collective security aims at replacing the unilateral use of force by collective peace enforcement under the control of the Security Council. From this point of view, self-defence appears as a contamination, inevitable as it may be, of the idea of collective security. On the other hand, by its very nature the system of collective security is not capable of effectively accomplishing its task by relying on its powers of collective intervention alone. Even under the post Cold War-conditions, the reasonably working UN-system is characterised by a number of inherent deficiencies concerning political decision making in the Security Council, the availability of operational resources and the capabilities to conduct military operations. In realistic terms the system is bound to fail if it does not integrate, to a tolerable degree, national initiative and resources. Consequently, the UN-system of collective security – which has not been designed as a matter of academic purity but of practical effectiveness – is conceptually to be understood as a combination of collective intervention and complementary instruments. The right of selfdefence is the primary device of this kind and, therefore, not merely a concession to the Member States but also a supportive element of the very system. The system-related limits of self-defence as laid down in Article 51 have to be seen against this background. First of all there is the duty of notification which has a purely formal character and does not bar the right of self-defence. Then the authority of the Security Council to review any claim of self-defence and to intervene in accordance with its own assessment. As always under Chapter VII the Security Council enjoys a considerable margin of appreciation when dealing with these questions. And finally the subsidiary and temporary character of the right of self-defence, reflecting the primacy of collective intervention as the main instrument of collective security. It is this final and crucial aspect which raises the most delicate difficulties and which depends most clearly on the way how the conceptual interrelation between self-defence and collective security is understood. Article 51 does not have the purpose to restrict self-defence as far as possible but to find a balanced position within the overall system. Four more specific conclusions can be drawn: – The aim of self-defence is more limited, but not fundamentally different from the aim of collective security. The protection of the existence and territorial integrity of Member States is an integral part of the task to maintain or restore international peace and security. – Consequently, the right of self-defence is suspended under Article 51 only if the measures taken by the Security Council are capable of producing an equivalent result, i.e.: if they are, in fact, sufficiently effective to stop the armed attack and thus to protect and restore the victim's territorial integrity. However, it is necessary to distinguish between defensive action and strategic counter-offensive. As regards the attacked state's defensive position an imminent stabilisation of the situation is required. By contrast, the option of a unilateral counter-offensive may already be suspended if the collective measures are likely to restore the integrity of the attacked state in the foreseeable future. It is mainly in this dimension that the subsidiarity of self-defence becomes effective. – With