In evidence before the Tribunal, Professor Meyrowitz stated that, of all those scholars who have expressly considered the topic, the substantial majority have concluded that the use of nuclear weapons would contravene international law. The minority opinion, predominantly American, is that the use of nuclear weapons would be lawful so long as their use complies with the standards of discrimination and proportionality. To be meaningful, this last assertion requires an answer to the question of whether the real (and not theoretical) use of nuclear weapons could be discriminating and proportionate. The Tribunal did not consider that the likely reality supports the assertion, and reached this conclusion based upon the evidence of the capabilities of existing nuclear weapons, the unlikelihood of a limited use of nuclear weapons and the medical and environmental consequences of their actual use.

Professor Boyle stated, "one might be able to conceive some totally insignificant situation in which a bomb could be blown off and perhaps not violate international law". Professor Griffith offered a few examples such as the use of a small 'clean' tactical weapon against an enemy ship in mid-ocean or against a small force in mid-desert. The Tribunal considered these examples to be unlikely.

In reality any major nuclear exchange would be an unprecedented human and environmental catastrophe proving a serious threat to the survival of all life on the planet. Even the use of a few tactical nuclear warheads would result in substantial incidental loss of civilian life and civilians would be subjected to unnecessary suffering far outweighing any immediate political or military objectives. There are the strongest religious and moral objections to the destruction of a society through the use of nuclear weapons. Indeed, it is difficult to identify any real value system that justifies their use. As for the rights of neutral states, missiles, which are not included within any of the treaties regulating air traffic, but which will inevitably fly over neutral territory are in breach of Article II of the fifth Hague Convention. The use of nuclear weapons would inflict considerable damage on neutral nations, most obviously upon Austria and Switzerland. It is the most extraordinary proposition that two warring states, engaged in a private conflict, may legitimately destroy their neutral neighbours.

Upon the evidence, the use of nuclear weapons cannot distinguish between combatants and non-combatants, that it could not represent a proportionate use of force, that it cannot be selective or discriminating, and that it violates the rights of neutral nations. In short, the use of nuclear weapons is unlawful. It is clear therefore that the use of nuclear weapons involves, inter alia, infringements the Charter of the United Nations, the Hague Conventions of 1899 and 1907 on the Law of War, the Geneva Conventions of 1949 and the Geneva Protocols of 1977. It is also clear that mere possession (certainly in terms of testing nuclear weapons) has already involved quite unlawful actions against civilian populations and exposed certain populations to unacceptable risks and actual damage.