Interpretation of international law by nuclear states tends to be that at present no rule of international law expressly prohibits the use of nuclear weapons. It is claimed by supporters of nuclear weapons that in the absence of such express prohibition, the use of such weapons against enemy combatants and other military objectives is permitted; that this use is permissible in legitimate self-defence under Article 51 of the UN Charter and it is certainly lawful merely to threaten their use in order to deter an attack.
This interpretation of the law is based on the "prohibitive theory" which allows any action unless it is expressly prohibited. The other possible interpretation is that of the "permissive theory" which holds that a State is free to do only what is expressly permitted.
It is hardly a surprise that States choose to follow the prohibitive theory as it concedes an enormous degree of freedom and discretion to governments in their conduct of international relations.
Such an argument presupposes that the anarchic situation prevailing among sovereign states is what the people of the international community intended when they drafted and enacted international law.
The US position for interpreting the law is based upon a case called The Lotus, decided by the Permanent Court of International Justice in 1927 which formulated the prohibitive theory. Professor Boyle pointed out in a well constructed argument that the Lotus Rationale was never intended to have any applicability to the international law of humanitarian conflict operable during warfare. It was intended to be used during peace time.
Professor Boyle continued by saying that any attempt to apply the Lotus Rationale runs up against the de Martens clause. This clause came to the opposite opinion to the Lotus Rationale for the employment of a new weapon, that the burden of proof lies upon the State wishing to use the weapon to justify the use of the new weapon under the existing norms for the international laws of humanitarian conflict. It must also be remembered that the key points of the de Martens Clause have been used repeatedly in treaties, conventions and declarations since 1907 (and since 1927, the date of the Rationale).
One can be drawn to the burning conclusion that if nuclear weapons cannot be used in a manner that does not violate the laws of war, then they cannot be used during a war in legitimate self defence either. So the Lotus Rationale is irrelevant to the issue whether or not the threat or use is legal.
Put another way, semantically the exponents of the "prohibitive theory" explain the lawfulness of nuclear weapons by the mere attachment of the adjective nuclear to the noun weapons. Many of the properties of nuclear weapons are clearly and repeatedly prohibited in international law. Is it reasonable for an inventor of a new weapon possessing the properties of weapons already clearly and extensively prohibited in international law to evade the law by the mere attachment of an adjective and call the new weapon, say, a widget weapon? Such a proposition is clearly absurd, and may well explain why legal justifications of nuclear weapons are in a distinct minority of opinion and usually commissioned by a nuclear power.
The Hague Conventions, as Professor Arbess stated, are a quite comprehensive code whose overall purpose is to provide restraint and accountability during the conduct of a war. The Tribunal and he find it impossible to believe that the use of dum-dum bullets or one single bayonet against one single military man would be prohibited, while the law would turn a blind eye to the use of the most indiscriminate weapon man has ever conceived. He continued by saying that the restriction of the use of nuclear bombs is implied from the existing international law and there is no more reason to be limited to the grammatical interpretation of international law than there is for domestic law.
Professor Meyrowitz and Professor Griffith were both more concerned with the argument that is often used, that as the laws of war predate nuclear weapons, and therefore fail to mention them, they therefore do not apply. Professor Griffith said that this interpretation "fails to heed the multi-faceted nature of the international law-creating system and is disregarding the fact that legal rules typically are interpreted to encompass matters not specifically mentioned and often not contemplated by their formulators".
Professor Meyrowitz gave a classic example of the adaptability of U.S. law, which dealt with the horse and buggy in its application to new technology, namely the car. He also stressed that there were numerous legal principles throughout the body of law that were formulated in antiquity, adopted by precedent and the common law process over time and articulated as the changes in technology occurred.
Indeed, the whole thrust of moral opinion which also happens to be embedded in numerous treaties executed in recent years, reaffirms case after case the unacceptability of nuclear weapons and other weapons of mass destruction.
The Tribunal is inextricably drawn to the conclusion that international law did apply to the nuclear powers who were cynically interpreting and manipulating international law for their own purposes of continuing to possess, develop and deploy nuclear weapons.