10 - What, eat the cabin boy? Uses of force that are illegal but justifiable

Summary

The letter killeth, but the spirit giveth life.

St. Paul, 2 Corinth. 3:6

Law that said what was necessary should not be done would seem an ass.

A.W. Brian Simpson, Cannibalism and the Common Law, p. 216 (1984)

When does a state's recourse to force violate its legal obligations under the UN Charter? Does the answer lie exclusively with the black-letter text of Article 2(4), or is the practice of UN organs and of the constituent states also relevant?

In its judgment in the Nicaragua case, the World Court set out its view on the interaction between practice and the legal norm pertaining to armed intervention:

The significance for the Court of cases of State conduct prima facie inconsistent with the principle of non-intervention lies in the nature of the ground offered as justification. Reliance by a State on a novel right or an unprecedented exception to the principle might, if shared in principle by other States, tend towards modification of customary international law.

True, practice cannot by itself amend a treaty, but, as the Court has also pointed out, the practice of a UN organ may be seen to interpret the text and thereby to shape our understanding of it. Persons other than lawyers may, however, be forgiven for thinking this a distinction without much difference. Whether its effect is characterized as modification or interpretation of text, practice matters.

This is particularly so when strict construction of treaty text leads to a reductio ad absurdum.