Through this article, the author will examine the Treaty on Nuclear Non-Proliferation (NPT) and the 1996 ICJ advisory opinion on nuclear weapons to see if the non-signatories of the NPT have any obligation under customary or treaty Law to disarm their nuclear stockpile.  
 
The advisory opinion delivered by the ICJ on legality of the threat or use of nuclear weapons is a cornerstone case in International Law. The Court opined that there was no source of Law that expressly prohibited the use or even possession of nuclear weapons. However, it further added that States must conform to Humanitarian and Self-Defence Laws that applied to all forms of weapons. In paragraphs 37-50, the Court looked at the issue of Deterrence, i.e. to examine if the threat of nuclear weapons on potential enemies was illegal and it came to the conclusion that the same was not necessarily unlawful.

To determine the issue on possession of such weapons, the Court looked at treaties, customary laws and the UN Charter itself. It concluded that there was no explicit law that forbade possession, other than the NPT but that would not be binding on its non-signatories. It also noted:
A weapon that is already unlawful per se, whether by Treaty or Custom, does not become Legal by reason of it being used for a legitimate purpose under the Charter.[1]
 
In paragraphs 68-73, the Court looked at the Customary status of treaties such as the NPT. It concluded that there was insufficient opinio juris to hold that such treaties indicated a clear Customary Law that would be universally binding on countries irrespective of their membership to such treaties. 
 
Customary status of the NPT:
The NPT categorises states as Nuclear Weapon States (NWS) and Non-Nuclear Weapon States (NNWS). If it can be argued, which it is by an increasing number of scholars that certain provisions of the NPT have entered the sacred territory of becoming Customary Law, then even the non-signatories of the NPT would be bound by such obligations, albeit via Customary Law and not the treaty itself. One would need to establish clear evidence of state practice and opinio juris to back such claims. Even in such situations, there exists the issue of the ‘persistent objector rule’. 
 
States like DPRK, Israel, Pakistan and India under the NPT would fall under the category of an NNWS. Under the treaty, the criteria for being an NWS is manufactured and exploded a nuclear weapon before January 1st, 1967.[2]  The status of Article VI is much clearer in that the NWS have continuously failed to fulfil their obligation of ‘negotiating in good faith to move to nuclear disarmament’. The ICJ noted the same in its Obiter Dicta in its 1996 advisory opinion.

Therefore, no State practice can be established and therefore, article VI would not be considered as a Customary Law. However, the focus of this article is the non-signatories to the treaty who fall under the NNWS category and would be governed by Article II of the NPT if it were to be considered a Customary Law. 
 
Article II requires each NNWS not to receive, nor transfer nuclear weapons or explosives directly or indirectly, not to manufacture or acquire by any means nuclear weapons. [3] The State practice test can strongly be argued for in the context of Article II. This stems from the fact that almost all countries are signatories to the treaty and for the most part have adhered to it. The notable exceptions include states like India, Pakistan, DPRK and Israel.

However, universal acceptance is not necessary for a Customary Law. The issue is in the lack of clear supporting opinio juris for Article II to become a Customary Law prohibiting every state other than the NWS from possessing nuclear weapons. This lack of explicit opinio juris comes from Article II itself in that it already encompasses these restrictions, and therefore, most States would view such an explicit opinio juris unnecessary. For the NNWS prohibition on acquisition and possession is apparent as they are already bound by it under the treaty. Therefore, it becomes extremely difficult to opine if there exists a clear opinio juris in the matter. 
 
In addition, objections have been raised on the grounds of the NPT being large multilateral contract treaty.[4] Therefore, since the treaty creates ‘common standards of legal obligations’ and not a universal set of obligations, these provisions cannot be considered a part of Customary International Laws.

However, it should be noted that there is no absolute clarity on the NPT being a contractual treaty. The boundaries between law-making treaties and contractual treaties’are not well defined in International Law and is in itself a subject of debate. In addition, the ‘quid-quo pro’ nature of the treaty does not necessarily mean that it is barred from becoming a Customary law. It is, therefore, the opinion of this author that because of the lack of explicit opinio juris that Article II of the NPT has not crystallised into a Customary International Law. 
 
The persistent objector Rule:
It was established by the author that article II of the NPT had not reached the status of being a Customary International Law. However, many scholars in the International Law community believe it has. Therefore, to outright dismiss it would not be prudent. This part of the article deals with non-signatories of the NPT under the assumption that Article II has crystallised into a Customary law. However, it was clearly established that the author does not believe so. 
 
If the averment that there exists a prima facie obligation on the non-signatories of the NPT to disarm their nuclear stockpile, then, the ‘persistent objector’ status of these States must be examined. The persistent objector rule has found some UN and Judicial acceptance and legitimacy. If a State continuously objects to a Customary Law during its early emergence and foundation, then, it is not bound by such a Law. 
 
There are two essential requirements for a State to be qualified as a persistent objector; 
The objection must be continuous in nature, i.e. A state cannot object only once and then claim the status of a persistent objector.

The continuous objection must be in the early stages, i.e. during its formation and emergence and not after it’s become binding on a State. A subsequent objection will not grant an exemption from having to follow the Law.

The idea of this rule is that States cannot be bound by something that they did not consent to bound on. [5] The problem lies in the fact that it is easy to establish consent for treaty-based Laws but hard to do for Customary Laws. A State’s consent can be determined by its silence on the Law. Therefore, it becomes important for States to persistently object in the early stages of the formation to establish a lack of consent. This also conforms with the idea of State autonomy. 
 
The Democratic People’s Republic of Korea (DPRK) is an extremely peculiar example when it comes to non-signatories being bound by Article II of the NPT as a Customary Law because it was initially a signatory and then withdrew itself from the treaty. There is a lot of debate whether DPRK could be considered as a persistent objector or not.[6]

The DPRK under the leadership of its leader Kim Jong Un has been very vocal about developing further Nuclear capabilities and about being in possession of Nuclear arsenal in forms of Weapons of Mass Destruction (WMD). The United Nations Security Council (UNSC) had asked DPRK to disarm itself and adhere to the requirements of the treaty much after its withdrawal from it. The DPRK has not been shy of making threats to the USA either. 
 
When it comes to States such as India and Pakistan, the persistent objector rule is easier to establish. Both India and Pakistan have been non-signatories from the beginning and have vocally condemned such treaties for their discriminatory nature. The clearest objection by India can be said to be the nuclear tests it carried out vide Pokhran-I in 1974 and its more successful sequel in Pokhran-II in 1998.

In terms of India’s Foreign Policy, it also has a No First Use (NFU) policy that states it would not use nuclear weapons as means of warfare unless attacked with nuclear weapons by an adversary first. This Policy is in opposition of everything the NPT stands for, and therefore, it is safe to say India and Pakistan would qualify as a persistent objector. Pakistan’s Prime Minister Imran Khan has also been vocal about its nuclear capabilities while referring to its disputes with India while talking about the dangers of two nuclear countries quarrelling. 
 
New Developments:
Recently, in the Marshal Islands (MI) case[7], MI had contended that nine nuclear States had failed to fulfil their obligations of eliminating the use of nuclear weapons altogether under Article VI of the NPT. The ICJ in its 1996 advisory opinion had held that:
the NWS States had a legal obligation to pursue in good faith negotiations to eliminate nuclear weapons.[8]

It contended that although, the DPRK, India, Pakistan and Israel were not bound by the NPT, they were bound by Customary International Law that required them to disarm their nuclear stockpile. The Case was eventually dismissed on the grounds of lack of jurisdiction which was raised by India.

The International Association of Lawyers against Nuclear Weapons (IALANA) submitted a paper/ resolution numbered A/CONF.229/2017/NGO/WP.12 in 2017,  to the UN in the ‘UN Conference to negotiate a legally binding instrument to prohibit nuclear weapons’ that contained express provisions titles Affirm the illegality of the use of Nuclear Weapons under Customary International Law.[9] The said resolution has not yet been passed and has no legal effect.

Conclusion:
The author has established his opinion that Article II has not crystallised into a Customary Law yet and worked under the assumption that even if it were to be considered a part of Customary International Law, the non-signatories to the NPT would be exempt from its binding effect by virtue of being persistent objectors. 
 
Bibliography:

• Latest Developments | Legality Of The Threat Or Use Of Nuclear Weapons | International Court Of Justice. 2020. Icj-Cij.Org. https://www.icj-cij.org/en/case/95
• Treaty On The Non-Proliferation Of Nuclear Weapons (NPT) – UNODA. 2020. Un.Org. https://www.un.org/disarmament/wmd/nuclear/npt/
• Treaty On The Non-Proliferation Of Nuclear Weapons (NPT) – UNODA. 2020. Un.Org.https://www.un.org/disarmament/wmd/nuclear/npt
• Green, James A. India's Status as a Nuclear Weapons Power under Customary International Law. National Law School of India Review 24, no. 1 (2012): 125-46.
• 2020. Icj-Cij.Org. https://www.icj-cij.org/files/case-related/160/160-20150316-WRI-01-00-EN.pdf.
• 2020. Brooklynworks.Brooklaw.Edu. https://brooklynworks.brooklaw.edu/cgi/viewcontent.cgi?article=1900&context=blr.
• Latest Developments | Obligations Concerning Negotiations Relating To Cessation Of The Nuclear Arms Race And To Nuclear Disarmament (Marshall Islands V. India) | International Court Of Justice. 2020. Icj-Cij.Org. https://www.icj-cij.org/en/case/158
• Latest Developments | Legality Of The Threat Or Use Of Nuclear Weapons | International Court Of Justice. 2020. Icj-Cij.Org. https://www.icj-cij.org/en/case/95
• 2020. Un.Org. https://www.un.org/disarmament/tpnw/pdf/A%20CONF.229%202017%20NGO%20WP.12.pdf

End-Notes:

1. Latest Developments | Legality Of The Threat Or Use Of Nuclear Weapons | International Court Of Justice 2020
2. Treaty On The Non-Proliferation Of Nuclear Weapons (NPT) – UNODA 2020
3. Treaty On The Non-Proliferation Of Nuclear Weapons (NPT) – UNODA 2020
4. Green, James A. India's Status as a Nuclear Weapons Power under Customary International Law. National Law School of India Review 24, no. 1 (2012): 125-46.
5. 2020. Icj-Cij.Org. https://www.icj-cij.org/files/case-related/160/160-20150316-WRI-01-00-EN.pdf.
6. 2020. Brooklynworks.Brooklaw.Edu.
7. Latest Developments | Obligations Concerning Negotiations Relating To Cessation Of The Nuclear Arms Race And To Nuclear Disarmament (Marshall Islands V. India) | International Court Of Justice 2020
8. Latest Developments | Legality Of The Threat Or Use Of Nuclear Weapons | International Court Of Justice 2020
9. 2020. Un.Org. https://www.un.org/disarmament/tpnw/pdf/A%20CONF.229%202017%20NGO%20WP.12.pdf.