Military Necessity - Weapons

Weapons

Military necessity also applies to weapons, particularly when a new weapon is developed and deployed. This usage was considered in Ryuichi Shimoda et al. v. The State (1963)

For the international law of war is not formulated simply on the basis of humanitarian feelings. It has as its basis both considerations of military necessity and effectiveness and humanitarian considerations, and is formulated on a balance of these two factors. To illustrate this, an example often cited in the textbooks may be given, of the provisions of the St. Petersburg Declaration of 1868 prohibiting the use of projectiles under 400 grammes which are either explosive or charged with combustible or inflammable substances. The reason for the prohibition is explained as follows: such projectiles are small and just powerful enough to kill or wound only one man, and as an ordinary bullet will do for this purpose, there is no overriding need for using these inhuman weapons. On the other hand, the use of a certain weapon, great as its inhuman result may be, need not be prohibited by international law if it has a great military effect.

— Ryuichi Shimoda et al. v. The State (1963)