2. The early age of nuclear testing in the atmosphere and the Partial Nuclear Test Ban Treaty (PTBT)

Since 1945, 2,052 nuclear explosions have been detonated in manufacturing or testing nuclear weapons.Footnote ² Such experiments were conducted not only by each of the nuclear powers now acknowledged by the NPT, but also by some other states trying to build their nuclear arsenal ‘outside’ the NPT or notwithstanding its regime.Footnote ³

The US was the first power to start testing nuclear, soon after the end of the Second World War. An intensive testing programme took place from 30 June 1946 to 18 August 1958 in the Marshall Islands, involving several atmospheric tests. The most powerful, known as the Bravo test, was conducted in the Bikini atoll and triggered a huge nuclear explosion, one thousand times bigger than the Hiroshima bomb.

Local people were removed from the islands, and were only allowed to return to their land years later. Once home, they still had to face harsh consequences, because of the catastrophic damages caused by radioactive contamination to human health, the environment, and properties in the area. Such contamination may well still linger. In 1983, by means of Section 177 of the Compact of Free Association with the Republic of the Marshall Islands, the US government declared that it was willing to ‘accept responsibility’ and to pay compensation for all the damage suffered by the population.Footnote ⁴

After 1958, the phase of US testing activity in the atmosphere came to an end, while further experiments took place underground, in the desert areas of Nevada. The latest tests, in the 1990s, were meant to develop new kinds of low yield devices and among those, in particular, the so-called nuclear ‘bunker-busters’.Footnote ⁵

The UK conducted an atmospheric test programme in Australia and off the Christmas Islands, from 1954 to 1958. After that, it ended experiments on its own, participating only in some joint test programmes with the US, in Nevada. The USSR and China started testing activity in the same period.Footnote ⁶

At the end of this first stage of nuclear tests, the states involved were able to conclude the Partial Nuclear Test Ban Treaty (PTBT), an international agreement prohibiting nuclear weapons tests in the atmosphere, in outer space and underwater. States parties undertake ‘not to carry out any nuclear weapon test explosion or any other nuclear explosion’ in the said areas: underground testing is not included in the prohibition. The ban is binding on states parties in relation to ‘any place under their jurisdiction or control’ and, in addition, the parties undertake to avoid any nuclear explosions which could cause radioactive debris outside their territorial limits (Article 1). The PTBT, in force since 10 October 1963, has been joined by 123 states, including the original parties, the US, the UK, and the USSR.

3. French nuclear tests and the International Court of Justice

France chose not to join the PTBT. In fact, at the time when the US and other states were concluding their nuclear tests in the atmosphere, France was just starting its experiments, with a first explosion in the Algerian Sahara desert, in 1958. Later on, the main testing site was moved to French Polynesia, by the Mururoa atoll, where atmospheric tests took place for more than 30 years.

Deep concern over the situation grew in Australia and New Zealand, as they feared lest their own territory and environment be put at risk. These states eventually brought two similar cases in front of the International Court of Justice (ICJ), seeking for provisional measures to inhibit France from conducting further testing. As for the merits, they asked the Court to declare that nuclear testing by France in the Pacific Ocean was contrary to international law.Footnote ⁷

As the PTBT was not binding for France – and in the absence of any general international law rule prohibiting nuclear tests – the applicants’ claims were based on the wrongful character of the damages caused by radioactive fallout on their territory, causing extremely dangerous effects to human health, the environment, and biological safety.Footnote ⁸ As both Australia and New Zealand strongly underlined, France had undertaken its nuclear activities without their consent, thus violating their sovereignty and their rights to territorial integrity. In addition, the applicant states argued that France had been infringing the fundamental principle of freedom of the high seas, by imposing a no-fly and no-shipping zone in the area where the tests were taking place.

The arguments of the parties were based on the existing norms of international law setting the traditional rules on the mutual respect of sovereignty by states. No further discussion took place about the possibility of considering nuclear tests contrary to any new general principles, or related to, for example, an obligation to protect the environment and/or human health. The Court of Justice, in fact, decided not to rule on the merits, after the French government had declared that the nuclear tests programme in the atmosphere had come to an end and would not have been resumed.Footnote ⁹

According to the Court, these unilateral declarations were considered binding on France and – being so – Australia and New Zealand had already reached their purpose. In other words, as the applicants were just asking the Court to state that tests were contrary to international law, they should have been satisfied – the Court held – once the binding character of the French declarations, under international law, had been established. Being so, the Court found that the case had become moot and that, for this reason, its jurisdiction failed.Footnote ¹⁰

Several years later, the Court took the opportunity to address the issue of nuclear testing with a different perspective, mentioning ‘obligations of States to respect and protect the environment’: even in this latest case, however, the Court did not rule on the merits, thus avoiding applying any rules involving those obligations.Footnote ¹¹

4. Latest developments

By the end of the last century, the main nuclear powers had declared that they would put an end to nuclear experiments, as their testing programmes were concluded: thus declared the US, Russia, China, and France. To date, they have behaved accordingly, and every unilateral moratorium on nuclear tests has been respected. However, the use of nuclear weapons is still considered to be an option by the national strategic security doctrine of each nuclear power.Footnote ¹²

Meanwhile, the nuclear programmes of other states raise different concerns. On the one hand, India and Pakistan claim to be, and have always been, legally free in this regard, as they did not ever ratify or even sign the NPT, which they perceive as unequal.Footnote ¹³ They openly admit to possessing nuclear weapons and that they are willing to develop their nuclear capabilities. The same can be said about Israel, a state that never joined the NPT, but whose possession of nuclear weapons, though not officially admitted, is considered to be an ‘open secret’.

On the other hand, North Korea (NK), a former party to the NPT, exercised the right of withdrawal from that treaty in 2003.Footnote ¹⁴ Since then, it has claimed to be free to pursue any nuclear project, being exempted from controls by the International Atomic Energy Agency (IAEA).Footnote ¹⁵ In 2006 and in 2009 some nuclear explosions in NK were detected and the situation until now has been challenging. The government in Pyongyang affirms that its nuclear activity is meant only to provide the energy supply the country needs. This affirmation is far from having the international community's confidence. In the aftermath of a Korean nuclear test in 2006, the UN Security Council declared that NK's continuing pursuit of nuclear weapons constitutes a threat to international peace and security.Footnote ¹⁶

Iran is also suspected to be well on the way to manufacturing nuclear weapons, in violation of the NPT, to which it remains a party. The Iranian government, however, rejects any charge of breach of the treaty, affirming that its present uranium enrichment activity is meant only for peaceful civil purposes, and that Western powers – by means of the UN economic sanctionsFootnote ¹⁷ – are willing to deprive Iran of its inalienable right to produce nuclear energy.Footnote ¹⁸ According to a UN report, issued in August 2012, Iran has recently doubled its capacity to enrich uranium, by means of underground nuclear facilities.Footnote ¹⁹

5. Nuclear weapon-free-zone treaties and the CTBT

In different areas of the world, some neighbouring states have adopted regional treaties banning nuclear weapons from their territories, so that their combined territories were considered nuclear weapon-free zones. Parties to such treaties undertake to renounce to ‘manufacture, or otherwise acquire or possess nuclear weapons’ and are also required to prevent the testing of any nuclear explosive device in their territories.Footnote ²⁰ All kind of nuclear tests – even underground – become unlawful in the areas where such treaties apply.

But further efforts were needed to reach a worldwide applicable ban. The UN Conference on Disarmament adopted, in 1996, the text of a universal CTBT. Each state, becoming a party to the CTBT, will undertake to avoid any nuclear test explosion performed either for military or for civil purposes ‘at any place under its jurisdiction or control’ (Article I). The prohibition is said to be ‘comprehensive’, because it bans every kind of explosive nuclear test: underground tests, this time, are included.Footnote ²¹

The CTBT provides for a highly sophisticated and efficient international monitoring system (IMS), capable of revealing nuclear explosions everywhere on Earth.Footnote ²² This system, meant to give immediate scientific evidence of any violation of the treaty, is already partially operating.Footnote ²³ It was by means of this monitoring system that the international community was made aware of the nuclear tests conducted in NK.Footnote ²⁴

The CTBT is not yet in force. In order for it to come into force, it needs to be ratified by 44 states, as specifically identified in its Annex 2. As a result of this, when any one of the 44 states fails to ratify the treaty, it nullifies all the other states’ efforts towards the total ban of any kind of nuclear tests and the full implementation of the IMS. France ratified the treaty after the conclusion of its testing programme in Polynesia, as had already Russia and the UK.

So far, only five states from the list in Annex 2 have failed to ratify the CTBT, namely China, India, Israel, Pakistan, and the US. India and Pakistan refuse not only to ratify the CTBT, but even to sign it, as a consequence of the approach they chose towards the NPT.Footnote ²⁵

As for the US, President Clinton was among the CTBT's major and genuine supporters.Footnote ²⁶ Notwithstanding his personal efforts, in 1999 the Senate refused to ratify the treaty. President G. W. Bush took a position opposite to that of President Clinton, stating that the US would never join the treaty.Footnote ²⁷ The programme of President Obama was to resume the ratification procedure, as Secretary of State H. Clinton assured at the 2010 NPT Review Conference, but this has not yet happened.Footnote ²⁸

China claims to fully support the CTBT, and analysts share the opinion that Beijing will probably ratify the CTBT, once the US has done so.Footnote ²⁹

6. The lack of relevant effects of signature of the CTBT, pending its entry into force

Given the paramount importance of this goal, it is worth investigating the possibility of attaching some legal effects to mere signature of the CTBT, pending its ratification, in the light of Article 18 of the 1969 Vienna Convention on the Law of Treaties. According to such an article, a signatory state is obligated to refrain from acts which would defeat the object and purpose of the treaty. When applied to the CTBT, the norm might be understood as to prohibit the signatory states from performing any nuclear test, even before they ratify the treaty.Footnote ³⁰

Although it seems evident that carrying out any nuclear test would be in contrast with the purpose of the treaty, such an interpretation of Article 18 would probably lead too far: mere signing of the CTBT – as such – cannot give rise to the same comprehensive ban on nuclear tests that the contracting states clearly intended to become effective only upon ratification by the required 44 states. The agreement on the list of states included in Annex 2 shows that the treaty was meant to become binding to the same extent and at the same time for each (and all) of those listed states.Footnote ³¹

Therefore, carrying out nuclear tests of any kind is not yet legally forbidden to any of the states which signed, or have already ratified, the CTBT (with only some kinds of tests being banned – as seen above – by means of different treaties, for states parties to them).Footnote ³²

7. The CTBT and the indefinite extension of the NPT

A meaningful legal connection between the NPT and the CTBT has been established by the consistent practice of the former treaty's parties, within the periodical Review Conferences, held every five years.

To clarify this point, it may be useful to recall some basic legal features of the NPT. As is widely known, this treaty does not provide for a total ban on nuclear weapons, since it rather ‘crystallizes’ the situation existing at the time of its signature. In fact, 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).Footnote ³³ These states were not required – in the short term – to take any specific measures to dismantle their nuclear arsenal, nor to put an end to activities aimed at manufacturing, improving, acquiring, or stockpiling nuclear weapons.Footnote ³⁴

In contrast, any other contracting state not entitled to claim the same position can currently join the NPT only under the status of non-nuclear weapon state (NNWS), thus accepting, without conditions, to be bound by Article II, which sets a radical prohibition to ‘manufacture or otherwise acquire nuclear weapons or other nuclear explosive devices’.

In such a way, the NPT grants only five states the possibility of legally keeping nuclear weapons. States thus ‘privileged’ are actually the same five that enjoy a prominent position within the UN, being permanent members of the UN Security Council. This fairly unbalanced situation, however, was not meant to last forever. As a condition of their legally granted major position, nuclear powers undertake – by means of Article VI of the same NPT – to

A definitive nuclear disarmament should be pursued by all states parties to the NPT, eventually leaving in the past the difference between nuclear and non-nuclear states.

The NPT was not originally meant to be operative forever. According to Article X(2), a conference was to be held twenty-five years after its entering into force, to decide whether the treaty was to continue in force indefinitely, or to be extended for an additional period. This special Extension and Review Conference took place in 1995, and the decision was made in favour of an unlimited extension, so the NPT is still operating according to its original terms, but without any expiry.

The consent to such indefinite extension, therefore, implied that NNWS accepted not to change their status under the NPT and, so, to renounce for good any nuclear military option. On the other side, however, nuclear powers’ prominent position cannot be considered as similarly granted without any time limit. Indeed, during the negotiations that led to the unlimited renewal, NNWS made it clear that their consent was conditional upon a renewed commitment of the NWS to the full implementation of Article VI, towards the achievement of the goal of ‘a treaty on general and complete disarmament, under strict and effective international control’.

8. The 13 practical steps

The 2000 NPT Review Conference agreed, by consensus, upon the so-called ‘13 practical steps’, a list of measures to be considered by each NWS party to the NPT as ‘systematic and progressive efforts to implement Article VI’. The first step consists of ‘signatures and ratifications, without delay and without conditions and in accordance with constitutional processes, to achieve the early entry into force of the Comprehensive Nuclear Test Ban Treaty’.Footnote ³⁵

The Final Document issued by the 2010 NPT Review Conference – as well as several documents and working papers submitted by states parties to the same ConferenceFootnote ³⁶ – underscores once more the ‘essential role’ of the CTBT not only as such, but also in relation to NPT's implementation, confirming the 13 practical steps set in 2000.Footnote ³⁷ The Vienna Group of Ten recently reaffirmed that:

Between the NPT and the CTBT some special link has thus been established, whose legal meaning this article will now discuss. Final documents – including the one setting the 13 steps – cannot be considered as legally binding international law agreements.Footnote ³⁹ Although adopted by consensus, they actually express no more than a political declaration of the common intent of the parties. Such documents belong to so-called soft law. That is why the ratification of CTBT cannot be seen as having become mandatory, for NPT parties, despite being mentioned as the ‘first step’ in the 2000 Final Document.

Nevertheless, soft-law documents agreed upon by consensus at the Review Conferences can be considered as ‘subsequent practice’ of the states parties to the NPT. According to Article 31(3) of the Vienna Convention (and/or the corresponding customary international law rules),Footnote ⁴⁰ ‘subsequent practice’ can provide elements to be taken into account in treaty interpretation. The possibility for (some) soft law ‘agreements’ – adopted by consensus – to play such a specific role in treaty interpretation can be ascertained from instruments encompassing a common understanding of all the parties to a treaty, as to the proper interpretation of it.Footnote ⁴¹

In such a way, the 13 steps contained in the 2000 Final Document – although not legally binding – can nevertheless provide some elements to take into account in the interpretation of Article VI of the NPT. This assumption calls for a deeper analysis of the meaning of Article VI, whose interpretation is still highly controversial between the nuclear and non-nuclear parties.

9. From the obligation to ‘pursue negotiations’ to the obligation to ‘conclude negotiations’ towards a multilateral disarmament treaty, according to the 1996 ICJ Advisory Opinion on the Legality of Threat or Use of Nuclear Weapons

According to the wording of Article VI, states are under an obligation ‘to pursue negotiations’. Assuming this wording involves an ‘obligation to negotiate’, it should be pointed out that such an obligation entails no more than a duty to pursue bona fide negotiations, not an obligation to conclude an agreement.Footnote ⁴² But some serious, meaningful negotiations, in any case, should at least be started, while no initiative of the kind has been taken towards the multilateral disarmament treaty envisaged by Article VI.

In the 1996 Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons, the ICJ took the opportunity to emphasize the continuing ‘vital importance’ of the goals set by Article VI of the NPT, to the interests of the international community as a whole. The legal relevance of the obligation concerned, according to the Court, ‘goes beyond that of a mere obligation of conduct’, being ‘an obligation to achieve a precise result: nuclear disarmament in all its aspects’.Footnote ⁴³ The Court, finding that the conclusion of a multilateral treaty would actually be the only way to achieve complete mandatory disarmament, refers to Article VI as providing a ‘twofold obligation to pursue and to conclude negotiations’, concerning all the states parties to the NPT.Footnote ⁴⁴ Substantially, it would be difficult not to consider that second obligation as equivalent to an obligation to conclude an agreement, even if the Court avoids these terms.

The Advisory Opinion clearly suggests that the obligation related to the final disarmament treaty can now be considered much more demanding than the mere obligation ‘to negotiate’ literally resulting from Article VI.Footnote ⁴⁵ The indefinite extension of the NPT, which came less than one year before the issuing of the Opinion, can actually provide an argument in favour of the interpretation given by the Court, as will be discussed below.

10. The continuing debate over Article VI of the NPT and its proper means of interpretation

Notwithstanding the authoritative and clear interpretation of the ICJ, the debate over Article VI is still lively, and even tough at times. According to some commentators, the Court's findings on Article VI – being just an obiter dictum and, even more so, being delivered within a non-binding decision – should not be overestimated.Footnote ⁴⁶

This opinion belongs to those who try to reduce to a minimum – or even to deny – the legally binding nature of Article VI. Evidence to support this assumption can be found in the negotiating history of the NPT. In such a way, the conclusion is reached that, while Article VI does require all states to pursue disarmament as a future ultimate goal, it was not meant to specify how and when such a goal has to be achieved.Footnote ⁴⁷ Supporters of this opinion argue that NWS are required to move – sooner or later – towards disarmament, by means of their choice, while the treaty mentioned in Article VI would be just one of the possible measures to be taken, not even the object of an obligation to negotiate.Footnote ⁴⁸

Some critical remarks can be opposed. First of all, such an interpretation seems in itself irrespective of international law, being grounded only on the consideration of the preparatory work.Footnote ⁴⁹

According to the Vienna Convention on the Law of Treaties, the preparatory work provides only subsidiary means of interpretation, in case the recourse to primary means ‘leaves the meaning ambiguous or obscure’ or ‘leads to a result which is manifestly obscure or unreasonable’.Footnote ⁵⁰

However, this convention applies only to treaties concluded after its entering into force, while the NPT actually preceded it. Moreover, the NPT encompasses some states that never joined the Vienna Convention, such as, precisely, the US. Because the interpretation needed is relevant to assess the US position towards Article VI, it is worth investigating the conformity of the rules of interpretation, set by the Vienna Convention, to customary international law.Footnote ⁵¹

The International Law Commission provides enough evidence of how international jurisprudence, before the Vienna Convention, used to deal with the choice of the proper means for treaty interpretation. Even according to general practice prior to the Vienna Convention, the possibility of grounding a proper interpretation only on the travaux preparatoires has to be excluded. The meaning of a treaty provision must be understood from the context of the treaty as a whole and, if the text of a convention is sufficiently clear in itself, then there will be no occasion to resort to preparatory work.Footnote ⁵²

Can Article VI of the NPT be considered sufficiently clear in itself, as read in the context of the whole treaty? The issues to be considered, for the purpose of this paper, are the legally binding nature of the obligation set by Article VI, and the definition of its contents.

11. The legally binding nature and the contents of the obligation set by Article VI of the NPT

Even if the ICJ opinion could be set aside as some suggest, other arguments could fully support the view of Article VI as legally binding. According to the law of treaties, as applied by the ICJ

When considering the NPT in the light of the abovementioned rule, any interpretation aimed at nullifying the obligation set by Article VI, by reading it as a non-legally binding commitment, would appear inconsistent with international law.

Nuclear powers have for decades been taking full advantage of compliance by their non-nuclear counterpart states, so that their military supremacy has not been gravely challenged since the NPT's entry into force. Moreover, by their consent to unlimited renewal of the treaty, NNWS agreed to remain under the obligation to avoid nuclear proliferation without any time limit. As some of those states point out, the commitment of NWS to progress towards disarmament was essential to their acceptance of the unlimited extension of the NPT, so that the early entry into force of the CTBT ‘was an integral part of the indefinite extension of the Non-Proliferation Treaty’.Footnote ⁵⁴

This obligation can by no means be ‘downgraded’ to a general pledge or a mere political commitment.

Given the legally binding nature of the obligation set forth by Article VI, it is then necessary to consider its contents. The provision requires NPT parties to ‘pursue negotiations’ on three different issues: cessation of the nuclear arms race, nuclear disarmament, and a treaty on general and complete disarmament. While the first two topics were to be dealt with ‘at an early date’, no time limit was set for the beginning of the negotiations towards the disarmament treaty. Of course, only NWS are committed to pursue effective measures in the two first sectors, while the general disarmament treaty should be concluded among all states parties.Footnote ⁵⁵

According to the supporters of the interpretation tending to reduce Article VI to no more than a recommendation, disarmament is to be pursued, but not (necessarily) by the conclusion of a treaty, as NWS would be free to adopt any measure of their choice to reach the result. This interpretation is at variance with the text of Article VI, taking into account all its different authentic versions: suffice it to consider how in each language Article VI refers to a ‘treaty’ (as the ultimate goal of the due negotiations) using exactly the same word that is in the name of the NPT.Footnote ⁵⁶ So, according to the text, the envisaged instrument of disarmament has to be a legally binding one, a ‘treaty’ of the same nature as the NPT. There is no case for enquiring into the negotiation history, on this point, as the text is clear.

The treaty to be negotiated has to be multilateral. The meaning and nature of this final achievement cannot be considered – by means of a reductive interpretation – as transposable into (a sum of) bilateral agreements, whose effects would actually be totally different and not adequate to pursue the final goal required by Article VI. According to international jurisprudence ‘the process of interpretation is a judicial function, whose purpose is to determine the precise meaning of a provision, but which cannot change it’.Footnote ⁵⁷

Nothing in the text of this article suggests that the envisaged agreement on disarmament could be concluded and become effective only among nuclear powers, leaving all the NNWS, as third parties, in a sort of separate world, with no legal title to claim compliance with the agreement. The treaty provided for by Article VI is still to be considered as a totally new achievement, substantially different from existing bilateral agreements leading to limited nuclear disarmament. Treaties of this kind, such as the new START, deserve to be highly appreciated by the international community, as they aim at some reduction of nuclear weapons, but are still far from being the kind of agreement that Article VI requires.Footnote ⁵⁸

Moreover, as for their political and strategic outcome, bilateral agreements between the two major NWS can hardly be seen as genuine disarmament measures, in respect of Article VI, as they rather appear to be arms control agreements.Footnote ⁵⁹ In order to assess the actual meaning of such agreements, some technical issues should also be considered, such as the type and age of the weapons to be destroyed. In fact, keeping and maintaining stocks of old nuclear weapons require expensive and technically sophisticated operations, so that destroying them might sometimes represent the most convenient solution.Footnote ⁶⁰

It is questionable, therefore, whether such bilateral agreements could actually pave the way for the final achievement that Article VI demands.

12. The inadimplenti non est adimplendum rule as applied to the NPT

Statements by the US and Russia, considering bilateral agreements to be evidence of full compliance with Article VI, sound as though they are, not grounded on good faith, while the two NWS fail to start any negotiations on a treaty on general and complete disarmament under strict and effective international control.Footnote ⁶¹ Many NNWS, especially non-aligned countries, have repeatedly stressed the need for full implementation of Article VI.Footnote ⁶²

Such a situation, after all, is weakening the position of nuclear states and the effectiveness of the NPT as a whole, when confronting alleged violations of the NPT by the non-nuclear states presumed to be planning the construction of nuclear weapons, such as North Korea and Iran. Obviously enough, these states would oppose any charge of non-compliance with Article II of the NPT by replying that even their nuclear counterparts are not respecting Article VI of the same treaty.

It would not be easy to challenge the consistency of this position with international law. The reciprocity principle, on which the general rule inadimplenti non est adimplendum is grounded, is applicable even in the relationships between states party to the NPT, as there is nothing in the text of the NPT allowing an interpretation aimed at excluding the operation of such a general rule.

According to well-established rules of general international law, as codified by Article 60 of the Vienna Convention, a ‘material breach’ of a multilateral treaty by one of the parties entitles the other parties – by unanimous agreement – to invoke the breach as a ground for terminating the treaty or suspending its operation in whole or in part. Moreover, a party especially affected by the breach could invoke it as a ground for suspending the treaty in whole or in part.Footnote ⁶³ For the meanings of these provisions, any violation by NNWS of the prohibition set by Article II of the NPT (i.e. by manufacturing or otherwise acquiring nuclear weapons) could surely amount to a material breach.

Nothing in the NPT seems to ‘rate’ the importance of the obligations mutually undertaken by non-nuclear versus nuclear parties and vice versa. These reciprocal obligations are linked in such a way that the commitment to disarmament by NWS under Article VI is seen as the essential counterpart (quid pro quo) of the commitment to non-proliferation of the NNWS.Footnote ⁶⁴

In fact, by accepting Article II, NNWS relinquish the possibility of ever retaining a military power equivalent to that of the NWS. The consent to such a substantial waiver in the field of national security cannot be deemed to be given by any sovereign state – as a subject of international law – without a counterpart of adequate (if not equivalent) weight.Footnote ⁶⁵

Thus, according to a good-faith interpretation, no support could be found in the text of the treaty for the assumption that only violations of Article II by NNWS are to be considered as a material breach, giving ground for application of the rule inadimplenti non est adimplendum, while breaches of Article VI would be only minor ones.Footnote ⁶⁶ So, it would be difficult to deny that the persistent refusal of the nuclear powers even to start any negotiation towards the conclusion of the agreement required by Article VI could equally be considered a material breach.Footnote ⁶⁷

As a matter of law, non-compliance with Article VI, just as much as non-compliance with Article II of the NPT, amounts to a material violation of the NPT, no matter how much less serious or visible the first case might appear to public opinion.

As long as NWS do not even plan negotiations for a multilateral disarmament agreement, any NNWS charged with violation of Article II, in order to find some legal grounds for justifying its conduct, could legitimately oppose the violation of Article VI of the same treaty by nuclear powers. The present position of the government of Iran is grounded on a similar reasoning.Footnote ⁶⁸

13. An obligation incumbent on nuclear powers party to the NPT, but failing to ratify the CTBT as yet

As seen above, it cannot be assumed that nuclear powers parties to the NPT are legally bound to ratify the CTBT. Even if their refusal to ratify prevents the treaty from entering into force, they cannot be held responsible for any wrongful act. At the same time, however, it would be equally misleading to assume that NWS continue to be totally free not to ratify, without any consequences in the field of international law.

The present position of the US and China seems to lie somewhere between these two positions. This can be ascertained by taking into account the possibility of some interaction between soft law – the political agreement on the 13 steps – and a hard-law instrument, such as the NPT.

Relevant practice adopted by consensus, and confirmed by each review conference since 2000, has attached primary relevance to the CTBT's ratification, as evidence of good will in pursuing Article VI goals. Even NWS shared this view, as consensus was reached among all the parties to the NPT, nuclear powers included. Indeed, reaching a common definition of the 13 steps runs in favour of their own interests: while the final goal is strongly reaffirmed, the indicated pace in pursuing it is actually allowed to be gradual. The final multilateral agreement could even be delayed as long as states abide by the 13 steps (as this conduct would avoid charges of non-compliance with Article VI).

In such a way, one may assume that ratification of the CTBT is the most significant step towards implementation of Article VI of the NPT. As a consequence, while ad hoc negotiations towards the envisaged multilateral disarmament treaty are lacking, it could nevertheless be assumed that states that do ratify the CTBT are – at least – acting in good faith and effectively towards the implementation of Article VI.

On the other hand, NWS that persist in refusing to join the CTBT are failing to offer such evidence of good faith in implementing Article VI, thus violating the general rule requiring states to behave in good faith during the execution of a treaty. In the long run, this could even amount to a breach of Article VI (as read in the light of the 13 steps), which is – as the ICJ puts it – ‘to achieve a precise result’.Footnote ⁶⁹

In order to prevent such charges, NWS choosing not to ratify the CTBT should otherwise provide evidence of their good faith: this could be done by giving detailed reasons for their conduct, both to their non-nuclear counterparts in the NPT and to the nuclear powers that have already ratified the CTBT. This duty amounts to a legal, although ‘minor’, obligation. In order to implement it, nuclear powers should at least issue some statement, at an official international level, to justify their delay. Of course, there would be no way to assess whether or not the motivation provided is genuine. However, this obvious limit is not in contrast with the existence of the obligation. In fact such a duty to provide motivation, without any possibility of challenging the bona fide of states’ allegations, is legally incumbent on states in cases of withdrawal from several disarmament agreements, including the NPT and the CTBT.Footnote ⁷⁰

Providing a clear explanation of a state's reasons for not ratifying the CTBT would demonstrate its commitment to Article VI of the NPT, for as long as it does not ratify it. However, it could be objected that this interpretation emphasizes the importance of the first step over the next 12. The opinion seems nevertheless consistent with the undiminished binding commitment to multilateral cooperation – based on equality between the parties and under effective international control – that Article VI requires. Among the 13 steps, only CTBT ratification implies acceptance of a treaty establishing multilateral cooperation, having the same basic legal features as the multilateral disarmament regime envisaged by Article VI. Hence, it can be assumed that this step – when compared to the next 12 – has a deeper meaning as evidence of goodwill in implementing Article VI.Footnote ⁷¹ And, indeed, it is not by chance that ratification of the CTBT is mentioned as the very first step to be taken.Footnote ⁷²

A unilateral moratorium on nuclear tests cannot be considered as equivalent to ratification of the CTBT for the purposes of Article VI, as interpreted taking the 13 steps into account. Unilateral measures fail to satisfy the rights of NNWS that – according to Article VI – are meant to become parties to the final disarmament agreement and, therefore, to be entitled to claim its respect under international law.Footnote ⁷³ Their position, of course, would be quite weak as each NWS, though declaring a moratorium, would remain free to withdraw its promise and resume testing activity.Footnote ⁷⁴