Preemptive Self Defense Under Article 51 of the UN Charter

January 25, 2010

Article 51 of the Charter of the United Nations expelled the right of preventive self defense from international law, if we are to say that it existed in customary international law before the adoption of the Charter. The syntax, grammar, intention and purpose of the article are clear prima facie. No country is entitled to exercise violence against other unless it is under armed attack of other.

The difficulty, however, resides in defining the initial moment of the armed attack, as well as the reach and scope of the action to which the attacked state is entitled. This has led to innumerable disputes and controversies. Yet, even the broader interpretations under this first interpretation would not admit preemptive self defense.

Notwithstanding the above, I believe it plausible to defend a different interpretation, which I nevertheless do not find convincing. According to this interpretation, the Charter does not preclude the right of self defense that preexisted to the enactment of the Charter.

This second interpretation finds its justification in what I would call a strong and power politics reading of the term inherent used in article 51. According to this reading, states have an inherent right to self defense, which, therefore, cannot be renounced. Using an analogy, just as 17^th and 18^th century contractualist philosophers contended that the parties to the social contract did not renounce to certain natural rights, such as the right of self preservation, in the context of contemporary international law it could be argued that states could not renounce to their right to self defense.

Furthermore, the trick of this argument is to assert that before the adoption of the Charter, states had a right to preemptive self defense, as a form of the more general right to self defense, under international customary law. This argument is, however, not convincing for two reasons.

First, it is unclear that under customary international law states have had a right to preemptive self defense. No historical or legal arguments seem to support such a conclusion. However, I do agree that middle point cases, such as those involving the need of anticipatory self defense, in the sense of the Caroline Doctrine, would be in the border line of an acceptable and reasonable interpretation of article 51.

Second, and most importantly, admitting the inherent right interpretation is counterintuitive as it randomizes the existence and stability of the United Nations itself, and therefore the pacta sunt servanda principle. The purpose of the United Nations was precisely to prevent violence and war, and to preclude jus ad bellum from the discretionary interpretations of states that, under almost any argument could “elaborate” arguments in order to “prove” supposed threats to their national security that would justify preemptive military action.

In conclusion, I believe that the inherent interpretation theory has simply gone way too far and endangers the integrity and strength of the United Nations system.