By Chandan Mohanty, KIIT Law School, KIIT University, Bhubaneswar.
The human kind witnessed the destruction that a nuclear weapon can do in the historical attack on Hiroshima and Nagasaki by the United States during the closing period of the World War II. The effect of the attack was horrifying and may be this is the reason it has not been used ever since.
After the World War II United Nations (hereinafter UN) was formed and one of many things that concerned the UN was the legality of the use of nuclear weapon.
In this article we will take an attempt to understand the present scenario regarding the legality of the use of nuclear weapon.
Article 2(4) of the UN Charter states-
“All members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations.”
In simple words Article 2(4) of the UN Charter restricts the use of threat or of force against the territorial integrity or political independence of any state. However, this article does not deal with nuclear weapon specifically. This article has taken the broader aspect of threat or force. Nuclear Weapon does come under the scope of threat or force but nowhere in this Article or in the UN Charter it is mentioned that the use or possession of nuclear weapon is illegal. Therefore it will be hard and difficult to say that the use or possession of nuclear weapon is illegal under the lights of Article 2(4) of the UN Charter.
On the other hand Article 51 of UN Charter states that-
“Nothing in the present Charter shall impair the inherent right of individual or collective self defense if an armed attack occurs against a member of the United Nations, until the Security Council has taken the measures necessary to maintain international peace and security.”
This Article of UN Charter talks about legality of the use of threat or force for the purpose of self defence and maintenance of internal peace and security. This article is also silent about the legality of the use of nuclear weapon. The principle governing the concept of self-defence states that the force used for self-defence should be proportionate to the threat faced. Therefore it won’t be wrong or illegal if any member of the UN uses nuclear weapon if the threat involves the use of nuclear weapon too. Since this article doesn’t deal specifically with the use of nuclear weapon, it will not be valid to relay on this Article only and provide a concluding answer to the question in hand i.e whether the use of nuclear weapon is legal or not?
Advisory Opinion of International Court of Justice
On December 20, 1994, the International Court of Justice (hereinafter ICJ) received a request from the UN Secretary General , made by the UN General Assembly for an urgent advisory opinion on the question “Is the threat or use of nuclear weapon in any circumstances permitted under international law?
The ICJ in its advisory opinion unanimously held that neither customary nor conventional international law specifically authorizes or prohibits the threat or use of nuclear weapon.
Further it held that a threat or use of nuclear weapons which is contrary to Article 2(4) and fails to meet all the requirements of Article 51 of UN Charter, is unlawful.
The opinion of the ICJ in this present advisory opinion can be concluded that the use or threatened use of nuclear weapons is illegal. However the ICJ couldn’t determine whether there is an exception to this finding when threat used is nuclear weapon itself or the survival of the particular state is at stake.
International Humanitarian Law
To have a definite conclusion we must take humanitarian law into consideration. In simple words, humanitarian laws can be defined as the laws during war. Humanitarian law has banned the use of many weapons like the famous “Dumdum Bullets” produced by the British Empire in a place called Dumdum of India. This bullet caused extra damage to the person who has been shot by it. To remove such unnecessary sufferings, the humanitarian laws banned the use of Dumdum Bullets.
However the humanitarian law has neither banned the use of nuclear weapon nor it has specifically allowed the use of nuclear weapon. But it is clear that no law or no treaty has specifically banned the possession or production of nuclear weapon.
Non Proliferation Treaty (NPT)
This treaty does not put a total ban on nuclear weapon. It rather crystalises the situation existing at the time of its signature.
According to Article IX (3), states already possessing or developing at a fixed date some nuclear military capability could join the treaty under the status of Nuclear Weapon State (NWS)
These states were not required to take any specific measures to dismantle their nuclear arsenal not to put an end to activities aimed at manufacturing, improvising, acquiring or stockpiling nuclear weapons.
Article VI of the Non Proliferation of Nuclear Weapon Treaty requires NPT parties to ‘pursue negotiations’ on three different issues:
- Cessation of the nuclear arms race
- Nuclear disarmament
- A treaty on general and complete disarmament
Though Article VI provides for cessation and disarmament of nuclear weapon, it is not mandatory for all the NWS to follow because it focuses on negotiations. Till now no NWS has given away its nuclear weapon.
The humanitarian law has neither specifically banned the use or possession of nuclear weapon which it has historically done with many chemical weapons and the famous Dumdum Bullet nor it has legalised the use of nuclear weapon.
Also Article VI of the Non Proliferation Treaty does not mandatorily provide for the cessation and disarmament of nuclear weapon for all Nuclear Weapon States. It rather focuses on negotiation to cease or disarm the nuclear weapon.
From the above mentioned treaties, legislation and opinion of ICJ, it will be valid to conclude that the production and stockpiling of nuclear weapon is not illegal. However the use of nuclear weapon is illegal if it does not fulfill all the requirements of Article 51 of UN Charter.
Hence it can be concluded that stockpiling of nuclear weapon is legal but the legality of its use is limited.
 Nuclear powers’ disarmament obligation under Treaty on the Non-Proliferation of Nuclear Weapons and the Comprehensive Nuclear Test Ban Treaty, leiden Journal of International Law, 2014