Introduction

The International Court of Justice, in its Advisory Opinion of 1996 on Legality of the Threat or Use of Nuclear Weapons, recognized two ‘cardinal principles contained in the texts constituting the fabric of humanitarian law’. The first is the principle of distinction between combatants and civilians, from which the Court deduced:

In any given international armed conflict, some weapons can be employed in a manner breaching the principle of distinction by being instruments of direct or indiscriminate attack against civilians (see infra, Chapter 5, II–III). The fact that this happens in a particular military action does not stain the weapons themselves with an indelible mark of illegitimacy, since in other operations the same weapons may be used within the framework of LOIAC. The issue, however, is whether a certain weapon is designed in such a way that, intrinsically, it is (in the Court's words) ‘incapable of distinguishing between civilian and military targets’. If so, the weapon is illegitimate regardless of circumstances. Putting it somewhat differently, ‘a weapon will be unlawful per se if it is incapable of being targeted at a military objective only, even if collateral harm occurs’. More often than not, the problem would relate to an inability (stemming, for instance, from a faulty guidance system in a long-range missile) to aim the weapon exclusively at military objectives.