The legal principles covering nuclear weapons have been evolving over centuries in many countries and civilizations. Greater impetus was provided by the Hague Conventions from 1899 onwards. Further codification took place with the Nuremberg Principles, and the International Court of Justice has put its mind to the lawfulness of nuclear weapons. Here are the fundamental principles of International Humanitarian Law as applied to weapons and warfare.

• Principle of Discrimination - to be lawful, weapons and tactics must discriminate clearly between military and non-military targets, and be confined in their application to military targets. Indiscriminate warfare is per se illegal, although indirect damage to civilians and civilian targets is not necessarily so.
• Principle of Proportionality - to be lawful, weapons and tactics must be proportional to their military objective. Disproportionate weaponry and tactics are excessive, and as such, illegal.
• Principal of Lawfulness - to be lawful, weapons and tactics must not violate any treaty rule of international law binding as between the parties.
• Principle of Necessity - to be lawful, weapons and tactics involving the use of force must be reasonably necessary to the attainment of their military objective. No superfluous or excessive application of force is lawful, even if the damage done is confined to the environment.
• Principle of Humanity - to be lawful, no weapon or tactic can be relied upon that causes unnecessary suffering to its victims, whether by way of prolonged or painful death, or in a form that is calculated to cause severe terror or fright. For this reason, weapons and tactics that spread poison, disease, or do genetic damage are illegal per se, as being weapons with effects not confined in the place and time of damage to the battlefield. Such a prohibition, under contemporary circumstances, extends to ecological disruption in any form.
• Principle of Neutrality - to be lawful, no weapon or tactic can be relied upon that seems likely to do harm to human beings, property, or the natural environment in neutral countries. A country is neutral if its government declares itself to be so and if it pursues a policy of impartiality in relation to armed conflict, including the avoidance of any kind of alliance relationship.
• Nuremberg Principles - the Nuremberg Principles serve to provide a summary of key principles of international law (of particular relevance to nuclear weapons).
• ICJ Advisory Opinion 1996 - the totality of the International Court of Justice’s Advisory Opinion and attached commentaries of the judges makes it clear that nuclear weapons are unlawful under international law. During the ICJ deliberations nobody was able to provide evidence of circumstances under which nuclear weapons could be used lawfully - just look at the legal principles set out above.
• Relevance of Civil Society Initiatives - the legal relevance of the Public Conscience is set out in Chapter 5 of Nuclear Weapons and International Law. There have been many initiatives to express the public conscience, including the London Nuclear Warfare Tribunal, the World Court Project, and the United Nations Open Ended Working Group on nuclear disarmament. The Hague Conventions resulted from civil society action.
• Individual Legal Liability - the Nuremberg Principles clarify that individuals responsible for crimes under international law are personally and individually liable, and cannot hide behind states or superior orders. In other words, anyone involved in the procurement or deployment of nuclear weapons assumes personal and individual legal liability and could be called to account on indictment before a competent legal authority. Do not participate in the procurement and deployment of nuclear weapons, without realizing you may be breaking international law.

Just pause for a moment and consider these fundamental legal principles. How is it possible for any nuclear weapon not to be in violation of some, if not all, of these principles?