Dr.iur. Daniel Rietiker
The announcement of 1st of February 2019 on the suspension and potential withdrawal by the USA from the Treaty on the elimination of intermediate-range and shorter-range missiles (hereafter: INF Treaty), a key instrument with Russia that has been a centerpiece of European security since the Cold War, followed by Russia’s prompt counter-reaction, has provoked massive national and international criticism. It will be argued in this paper that this step is not only unwise and dangerous, but also problematic under international law.
The present analysis focuses on legal issues insofar as its author believes that the current debate is dominated, even monopolized by consideration of policy. International law adds a useful further aspect to the debate since it provides for procedures entailing important restrictions to the unilateral behaviour of States. The special role of treaties in international relations, and in particular for international peace and security, has been recognized and well expressed in the preamble of the 1969 Vienna Convention on the Law of Treaties (hereafter: VCLT):
The States Parties…
1. Considering the fundamental role of treaties in the history of international relations,
2. Recognizing the ever-increasing importance of treaties as a source of international law and as a means of developing peaceful co-operation among nations, whatever their constitutional and social systems…
Three elements will be discussed in the present paper, namely the obligation to settle international disputes peacefully, the obligation to negotiate in good faith, as well as the main question whether the suspension, potentially followed by definitive withdrawal by the USA from the INF Treaty, meets the procedural and substantive requirements imposed by the relevant legal provisions.
I. The obligation to settle international disputes peacefully
It is a well established principle of international relations that disputes between States have to be settled peacefully.
A “dispute” has been defined as “a disagreement on a point of law or fact, a conflict of legal views or of interests between two persons.” From our point of view, there is no doubt that, between the USA and Russia, there exist a genuine dispute, namely a disagreement on the issue of compliance with the INF Treaty.
Article 2 § 3 of the UN Charter spells out the duty in the following terms:
All Members shall settle their international disputes by peaceful means in such a manner that international peace and security, and justice, are not endangered.
In addition, Article 33 of the Charter draws an – inexhaustive – list of possible methods of dispute settlement:
The parties to any dispute, the continuance of which is likely to endanger the maintenance of international peace and security, shall, first of all, seek a solution by negotiation, enquiry, mediation, conciliation, arbitration, judicial settlement, resort to regional agencies or arrangements, or other peaceful means of their own choice.
It derives from these two provisions that, whereas the parties to a dispute are free to choose the method of settlement of the dispute, they are obliged to seek a peaceful solution to their disputes. In other words, it is doubtlessly a legally binding duty.
The 1970 Declaration on Principles of International Law Concerning Friendly Relations and Co-operation among States in Accordance with the Charter of the United Nations (the “Friendly Relations Declaration”), considered as codification of the principles of the UN Charter, provides moreover for what follows:
States parties to an international dispute, as well as other States, shall refrain from any action which may aggravate the Situation so as to endanger the maintenance of international peace and security, and shall act in accordance with the purposes and principles of the United Nations.
There is no doubt that the prolongation of the dispute around the INF Treaty, with the possible termination of the treaty, is capable of endangering the maintenance of international peace and security. This view has been expressed many times since the USA had started to warn Russia that it would leave the treaty. Moreover, the preamble of the INF Treaty stresses the importance of that instrument for international peace and security in the following terms:
The United States of America and the Union of Soviet Socialist Republics, hereinafter referred to as the Parties,
Guided by the objective of strengthening strategic stability,
Convinced that the measures set forth in this Treaty will help to reduce the risk of outbreak of war and strengthen international peace and security (…)
Futhermore, the discussion around the INF Treaty and whether it has been breached is a dispute relating to an international treaty that, according to the preamble of the VCLT,
should be settled, like other international disputes, by peaceful means and in conformity with the principles of justice and international law.
In the INF Treaty, the Parties had agreed to resort, in the first instance, to bilateral consultations or negotiations within a “Special Verification Commission”. In fact, Article XIII provides for the following:
…the Parties…have agreed:
To promote the objectives and implementation of the provisions of this Treaty, the Parties hereby establish the Special Verification Commission. The Parties agree that, if either Party so requests, they shall meet within the framework of the Special Verification Commission to:
(a) resolve questions relating to compliance with the obligations assumed; and
(b) agree upon such measures as may be necessary to improve the viability and effectiveness of this Treaty.
The duty to resolve a dispute within this Special Verification Commission can be considered an application of Article 33 of the UN Charter. But unlike in other arms control treaties where the Parties agreed on specific mechanisms of settlement in case of differences in interpretation and application of a treaty provision, the USA and Russia did not insert into the INF Treaty a clause concerning resolution of a dispute when the Special Verification Commission finds itself in a stalemate, as it seems to be the case right now. This does, however, not change their duty under Article 2 § 3 and 33 of the UN Charter insofar as they have to agree on a mechanism of their choice to settle peacefully their current dispute.
To sum up this first section, the duty to settle a dispute peacefully restricts the freedom of the States Parties to withdraw, without weighty reasons, from the INF Treaty, a crucial treaty for international peace and security. The international community is now requested to assist the two States, by providing good offices or mediation, with a view to finding a way out of this crisis and to save the treaty or replace it by something equivalent or even more effective.
II. The obligation to negotiate in good faith, in general and towards nuclear disarmament in particular
The most basic and important mechanism of friendly settlement of disputes are negotiations, which have to be conducted in good faith. The ICJ has made clear that States entering into negotiations…
are under an obligation to enter into negotiations with a view to arriving at an agreement (…); they are under an obligation so to conduct themselves that the negotiations are meaningful, which will not be the case when either of them insists upon its own position without contemplating any modification of it.
The current situation is characterized by total lack of communication, flexibility and readiness for compromise. Daryl G. Kimball (Arms Control Association) claims that the recent Russian offer to exhibit the 9M729 has been deemed insufficient by the USA because it doesn’t allow for independent verification. He adds that US officials could propose an alternative that does so, but they do not seem to pursue this path because they believe the missile violates the treaty anyway. The USA Government has moreover expressed its clear intent to leave the treaty, on December 21, when opposing a Russia-sponsored UN General Assembly resolution calling for the preservation of the treaty and for the two countries to consult on compliance with its obligations. Indeed, it seems clear that certain people around President Trump, in particular US National Security Adviser John Bolton, simply try to sabotage both the INF treaty – as well as the New START Treaty – without giving reasonable and logical explanations for this or presenting alternative measures.
On the other hand, the US Government is not recognizing the validity of the Russian concerns that US Mk-41 launchers, that are part of the Aegis Ashore missile defense deployment in Romania, could be used to launch offensive missiles. This is a valid concern and one that could be addressed through site visits or other confidence-building arrangements.
Moreover, according to Article 31 VCLT, considered to be of customary nature and therefore binding also on States not having ratified that instrument, such as the USA, a treaty shall be interpreted “in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose”. Concerning the last two elements of this general rule on interpretation, namely the “context” and the “object and purpose”, it derives from the preamble of the INF Treaty that this instrument has to be considered a tool aimed at realizing the disarmament obligations under Article VI NPT:
…the States Parties…
Mindful of their obligations under Article VI of the Treaty on the Non-Proliferation of Nuclear Weapons (…)
It should be recalled that Article VI NPT provides for the obligation to
pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament…
The International Court of Justice confirmed, in its 1996 Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons, unanimously, that “there exists an obligation to pursue in good faith and bring to a conclusion negotiations leading to nuclear disarmament in al1 its aspects under strict and effective international control.”  This duty is imposed on all States but, logically, such an obligation is addressed above all to the Nuclear Weapons States (NWS), in particular the USA and Russia, by far the most powerful NWS.
This two-folded duty to negotiate in good faith, deriving from both general international law and Article VI NPT, places another important restriction on the suspension and potential withdrawal from the INF Treaty. According to Kimball, a withdrawal from the INF Treaty, coupled with a non-extension of the START treaty, would constitute a violation of Article VI NPT. A Russian representative’s remark that US withdrawal from INF “is the start of a full-fledged arms race” goes in the same direction.
III. Analysis of the US declaration suspending and potentially withdrawing from the INF Treaty
A. Lack of clarity in the US declaration
For a couple of years already, the US Government has been claiming violations of the INF Treaty allegedly committed by Russia. On 4th December 2018, US Secretary of State Michael Pompeo announced that “the United States today declares it has found Russia in material breach of the treaty and will suspend our obligations as a remdy effective in 60 days unless Russia returns to full and verifiable compliance.” On 1st February 2019, finally, the White House issued the following statement:
For far too long, Russia has violated the Intermediate-Range Nuclear Forces (INF) Treaty with impunity, covertly developing and fielding a prohibited missile system that poses a direct threat to our allies and troops abroad. Tomorrow, the United States will suspend its obligations under the INF Treaty and begin the process of withdrawing from the INF Treaty, which will be completed in 6 months unless Russia comes back into compliance by destroying all of its violating missiles, launchers, and associated equipment. Our NATO Allies fully support us, because they understand the threat posed by Russia’s violation and the risks to arms control posed by ignoring treaty violations.
The United States has fully adhered to the INF Treaty for more than 30 years, but we will not remain constrained by its terms while Russia misrepresents its actions. We cannot be the only country in the world unilaterally bound by this treaty, or any other. We will move forward with developing our own military response options and will work with NATO and our other allies and partners to deny Russia any military advantage from its unlawful conduct.
My Administration remains committed to effective arms control that advances United States, allied, and partner security, is verifiable and enforceable, and includes partners that fulfill their obligations. For arms control to effectively contribute to national security, all parties must faithfully implement their obligations. We stand ready to engage with Russia on arms control negotiations that meet these criteria, and, importantly, once that is done, develop, perhaps for the first time ever, an outstanding relationship on economic, trade, political, and military levels. This would be a fantastic thing for Russia and the United States, and would also be great for the world.
In sum, and without providing for more details or stating the legal basis for their action, the USA declared that they would suspend the application of the treaty for six months and, in case Russia would not be in compliance by then, definitively withdraw from the treaty. From the outset, two different provisions enter into consideration, namely Article XV of the INF Treaty, providing for a special withdrawal clause, and Article 60 of the VCLT, containing a clause allowing a victim of a breach of a treaty to suspend or withdraw from it under certain circumstances.
It will be shown below that Article 60 VCLT is, on the one hand, more specific than Article XV of the INF Treaty since it spells out the “breach” (or “violation”) of a treaty directly, but more general, on the other hand, insofar as it is contained in the VCLT, establishing general rules and principles for treaties (sometimes called the “treaty of treaties”), and not in the INF Treaty as such. As a matter of fact, paragraph 4 of Article 60 VCLT provides for the following clause:
The foregoing paragraphs are without prejudice to any provision in the treaty applicable in the event of a breach.
It is suggested here that this provision does not categorically exclude the application of other clauses relevant in the event of a breach, such as Article XV of the INF Treaty. It is possible, from our point of view, that a particularly serious material breach of a treaty within the meaning of Article 60 VCLT constitutes in the same time also events capable of triggering the application of Article XV of the INF Treaty. The threshold would however have to be considerably high. To the extent that the general rules of the VCLT are not contradicted or altered by another treaty text, the general rules are still applicable. Only in a situation of contradiction, the principle of lex specialis derogate lege generali applies.
Having said this, the scope of application of these two provisions is nevertheless rather different and, as a result, the relationship between them and their application to the present situation not entirely clear which, coupled with the vague terms of the US declaration, is not beneficial to legal certainty. In fact, on the one hand, the US allegations of repeated violations of the treaty by Russia fit better to Article 60 VCLT, but the period of six-months announced by the USA before the withdrawal enters into force ressembles more a measure taken under Article XV of the INF Treaty, on the other. In other words, the US Government seems to pick and choose the ingredients from those two clauses in a way it considers it appropriate for its own purposes, as it was a dish “à la carte”.
B. Article XV of the INF Treaty: “Extraordinary events” clause
Article XV of the INF Treaty contains a standard withdrawal clause which has traditionally been included in arms control treaties, and reads as follows:
1. This Treaty shall be of unlimited duration.
2. Each Party shall, in exercising its national sovereignty, have the right to withdraw from this Treaty if it decides that extraordinary events related to the subject matter of this Treaty have jeopardized its supreme interests. It shall give notice of its decision to withdraw to the other Party six months prior to withdrawal from this Treaty. Such notice shall include a statement of the extraordinary events the notifying Party regards as having jeopardized its supreme interests.
Indeed, one of the common features of arms control treaties is the fact that they are concluded for unlimited duration but contain very similar withdrawal clauses. Already the 1963 Partial Test Ban Treaty (PTBT) provided for such a clause. This clause is sometimes referred to as the “extraordinary events” formula and its application is subject to several formal and substantial conditions. It served as a template for arms control treaties concluded later. For instance, a very similar clause was inserted in the 1968 NPT, in the 1996 Comprehensive Test Ban Treaty (CTBT) or, more recently, in the 2017 Treaty on the Prohibition of Nuclear Weapons (TPNW).
For the following reasons, invoking that clause in the current dispute between the USA and Russia seems problematic under international law.
Suspension does not comply with conditions of Article XV
On 4 December 2018, as mentioned above, Pompeo declared that the USA has found Russia in material breach of the treaty and will suspend its obligations in 60 days unless Russia returns to full and verifiable compliance. Morover, on 1st of February 2019, the US Administration declared that it will suspend the application of the treaty with immediate effect, i.e. from 2nd February 2019 onwards, willing to move forward with developing their own military response options. In our understanding, nothing in Article XV suggests that such a suspension is permitted. A suspension, instead of withdrawal, would certainly be legally possible and even preferable in light of the principle “in maiore minus”, but only after the “cooling-off” period of six-months.
Moreover, it is more than doubtful whether the option of “suspension” of the INF Treaty by the USA is not misconceived. In reality, suspension means that the treaty becomes inoperative for the parties for a particular time though the treaty regime itself is not affected. States usually resort to suspension, for instance, if they temporarily encounter difficulties concerning the performance of their obligation under the treaty. In the present case, however, the US suspension seems to be aimed at imposing an ultimatum on Russia and, in the same time, using the time of suspension for building up own military response options, possibly in cooperation NATO partners, as it derives from the declaration of 1st February 2019. From our point of view, such a scenario is clearly not the purpose of a suspension of a treaty. Moreover, suspension should be limited in time and be terminated by the full execution of the treaty by the parties. In the INF Treaty dispute, however, there seems only very little or no willingness to return to full treaty performance after expiration of the six-months period.
As a result, the US declaration appears to be clearly contrary to the unambiguous text of Article XV of the INF Treaty and the purpose of “suspension” of treaty operation.
Broad, but not illimited discretion of the USA
The formal and substantive conditions of the withdrawal clauses inserted in arms control treaties, interpreted in good faith, contain certain guarantees against abusive or hasty withdrawal.
It is undeniable that the phrase “extraordinary events related to the subject matter of this Treaty [that] have jeopardized its supreme interests” is a rather vague formulation. Moreover, it is a so-called “self-judging clause” insofar as it leaves it in principle to the State Party willing to get rid of a treaty to define a certain event as threatening its supreme interests (“if it decides…”). As a result, the States relying on such a clause enjoy a priori a broad margin of appreciation, which is nevertheless not illimited. Restrictions on the States’ discretion flow, in particular from the principle of good faith, an overarching principle in international relations, as well as from the principle of effectiveness, sometimes also referred to as “effet utile”.
In fact, the very reason behind the procedural obligation of notification is to provide other States with information about what the relevant State claims under the treaty exception clause. If the idea behind such a clause was that the State should be absolutely free to determine the legality of its withdrawal, then there would be no reason at all to impose on it a duty to notify regarding the rationale for withdrawal. In other words, the duty to notify inherently implies that there is a limit separating what can validly be claimed under emergency clauses from what cannot. The judgment on this is not the exclusive property of the State invoking the extraordinary events. Denying this would contradict the above mentioned principle of “effet utile”, according to which treaty provisions cannot be considered as redundant and inutile.
Regarding the INF Treaty, the State Party intending to withdraw “shall give notice of its decision to withdraw to the other Party six months prior to withdrawal from this Treaty[, and] such notice shall include a statement of the extraordinary events the notifying Party regards as having jeopardized its supreme interests.” The US Administration declared publicly that it would send a formal declaration to Russia informing them formally about the suspension, followed, if needed, by withdrawal from the INF Treaty. The declaration that the USA intended to address to the Russian Government is a diplomatic document and, therefore, probably not publicly available. In any event, considering all the circumstances, is not expected to be more precise than the vague public announcement made by the US Governement on 1st of February (see above).
The US declaration likely to fail the “extraordinary events” test in the present circumstances
The States must be facing “extraordinary events related to the subject matter of this Treaty [that] have jeopardized its supreme interests.” Lichterman and Burroughs suggest that the US administration has not made the case that the missiles in question pose a threat that significantly affects the military balance between Russia and the very large and capable forces of the United States and its NATO allies, much less constitute an “extraordinary” development jeopardizing US “supreme interests.”  They recall that President Trump has also indicated that withdrawal is premised in part on a buildup of intermediate-range missiles by China, which is not a party to the treaty. From their point of view, here too no case has been made that these missiles, which are based in China’s national territory, are best answered in kind by US deployment of intermediate-range missiles. Nor has it been demonstrated that peace and stability in that region or the world will be enhanced by repudiating the treaty rather than seeking more comprehensive arms control measures aimed at braking an emerging multipolar arms race.
One of the rare examples where such a withdrawal clause has been used in a bilateral arms control treaty is the announcement of the US Government to withdraw from the ABM Treaty on 13 December 2001, i.e. only three months after the terrorist attacks of 11 September 2001. The following paragraphs are only a part of the longer declaration:
Today, I have given formal notice to Russia, in accordance with the treaty, that the United States of America is withdrawing from this almost 30-year-old treaty. I have concluded the ABM Treaty hinders our government’s ability to develop ways to protect our people from future terrorist or rogue-state missile attacks.
Today, as the events of September the 11th made all too clear, the greatest threats to both our countries come not from each other, or other big powers in the world, but from terrorists who strike without warning, or rogue states who seek weapons of mass destruction.
We know that the terrorists, and some of those who support them, seek the ability to deliver death and destruction to our doorstep via missile. And we must have the freedom and the flexibility to develop effective defenses against those attacks. Defending the American people is my highest priority as Commander in Chief, and I cannot and will not allow the United States to remain in a treaty that prevents us from developing effective defenses. (…) 
Even thought that declaration was, compared with the recent INF declaration, much more elaborated and identified a rather concrete, well defined threat to the nation, it was still considered insufficient by certain authors. The criticism expressed indicates that it is more than doubtful whether the test of “extraordinary events jeopardizing the supreme interests” has been met in the case of the INF Treaty.
C. Article 60 VCLT: Termination or suspension of the operation of a treaty as a consequence of its material breach
In addition to the special clause inserted in the INF Treaty (Art. XV), the US administration seems to rely, at least implicitly, on Article 60 VCLT, which is recognized as reflecting customary international law regarding bilateral treaties, and that reads as follows in its relevant part:
1. A material breach of a bilateral treaty by one of the parties entitles the other to invoke the breach as a ground for terminating the treaty or suspending its operation in whole or in part.
3. A material breach of a treaty, for the purposes of this article, consists in:
(a) a repudiation of the treaty not sanctioned by the present Convention; or
(b) the violation of a provision essential to the accomplishment of the object or purpose of the treaty.
Generally speaking, Article 60 VCLT leaves the final decision to the subjective judgment of the innocent party. It appears from the outset that, within Article 60 § 1 VCLT, suspension only of the treaty is explicitly mentioned here, contrary to what has been observed under Article XV of the INF Treaty. The victim of a violation of a treaty enjoys nevertheless not absolute discretion and must be guided, first, by good faith, which means that it cannot invoke a breach merely as a pretext for certain courses of action. In that respect, this provison does not differ much from what has been observed under Artile XV of the INF Treaty. Second, the result must be proportionate to the nature and intensity of the breach and third, in multilateral treaties, the interests of the other States Parties must also be considered. We would add that, in a treaty such as the INF Treaty, even though only a bilateral instrument, even the interests of the international community as a whole must be considered, as will be explained below.
No automatic supsension or withdrawal
It derives from the formulation of Article 60 § 1 VCLT that the injured Party is not empowered unilaterally to suspend or terminate the treaty. Rather, it has the right “to invoke the breach as a ground for suspension or termination” of the treaty and, in other words, to seek the peaceful settlement of disputes. Indeed, a breach of a treaty, however serious, does not ipso facto put an end to the treaty, and it is not open to the injured State simply to allege a violation of the treaty and pronounce the treaty to be terminated. As such, Article 60 VCLT, rather than envisaging reprisals, aims at restoring the contractual balance.
In case a suspension or withdrawal is based on one of the grounds flowing from the VCLT, its Article 65 provides for a procedure to be followed with respect, inter alia, to suspension or withdrawal from treaties. Article 65 § 1 VCLT indicates that the Party withdrawing from the treaty or suspending its operation must notify the other parties of its claim. Similar to what has been observed under Article XV of the INF Treaty, the notification must indicate the measure proposed to be taken with respect to the treaty and the reasons therefor. Para 2 and 3 add that, if, after the expiry of a period which, except in cases of special urgency, shall not be less than three months after the receipt of the notification, no party has raised any objection, the party making the notification may carry out the measure proposed. If, however, objection has been raised by any other party, the parties shall seek a solution through the means indicated in article 33 of the Charter of the United Nations.
Even though this provision might appear complex, its customary nature doubtful and States hesitant to use it in practice, it nevertheless establishes “procedural checks-up upon allegedly arbitrary action” or might offer inspiration for similar procedural safeguards and, as a result, is capable of preventing differences in respect of termination of a treaty from evolving into a major dispute. It is obvious that any procedural safeguard of that kind has been taken by the US Government, in particular no minimum period of three months has been observed for the suspension of the INF Treaty. Regarding this latter aspect, it would be hard to defend the case that the circumstances of the current situation call for “special urgency”. Moreover, in spite of the fact that Russia has always refuted the allegations of material breach, the US Government has neverthless created faits accomplis by unilaterally suspending and threatening to definitively withdraw from the treaty.
As a result, insofar as the Parties may only “invoke” the grounds for suspension and withdrawal under Article 60 VCLT, the treaty remains in principle in force until appropriate procedures with a view to settling the dispute peacefully (Article 33 of the UN Charter), as described above, have been completed.
Higher values and interests of humanity
The party willing to leave the treaty would have to prove a material breach, which is defined, inter alia, as the “violation of a provision essential to the accomplishment of the object or purpose of the treaty” (60 para 3 b VCLT). The term “material breach” has to be narrowly construed. First of all, it has been observed above that a violation of the INF Treaty by Russia is not sufficiently established. Second, even assuming this is the case, it is not certain whether the violation would be serious enough to justify supension and/or withdrawal, in particular whether it concerns a “provision essential to the accomplishment of the object and purpose of the treaty.” From our point of view, an arms control treaty such as the INF Treaty, even if only a bilateral instrument, has been concluded not only for the mutual, private interests of the two States Parties, but for the common interest of humanity. This derives clearly from the preamble of the INF Treaty:
The United States of America and the Union of Soviet Socialist Republics (…)
Conscious that nuclear war would have devastating consequences for all mankind”
The prompt and almost unanimous condemnation by the international community of the suspension of the treaty by the USA is another indication that this instrument has a reach that goes far beyond the two States Parties. The reason for that lies in the special features of nuclear weapons that, as the ICJ held,
cannot be contained in either space or time. They have the potential to destroy all civilization and the entire ecosystem of the planet.
In a recent article in the New York Times, Professor Theodore Postol (MIT) expressed the threat of nuclear weapons to humanity in the following terms:
In fact, existing nuclear weapons systems can do anything imaginable, and much more that is unimaginable. It is the unimaginable capabilities of these weapons that must take center stage when considering the giant and still unknown terrors and threats they pose to global stability and humanity’s future.
Seen from this angle, we are of the opinion that the USA and Russia, by far the most powerful NWS, play the role of trustees for the entire international community and future generations. German Chancellor Angela Merkel stressed the special importance of the INF Treaty for Europe during the Munich Security Conference in February 2019, considering the INF Treaty termination discussion…
a very interesting constellation: a treaty, which was basically concluded for Europe, a disarmament treaty, which concerns our security, has been terminated by the USA and Russia as the successor of the Soviet Union; and now we are sitting here and will try with our elementary interests everything to enable further disarmament steps. Because the answer cannot be blind arms race”
It is suggested here that, in light of what precedes, renonuncing too casually a key arms control instrument due to mutual misunderstandings and lack of communication and willingness to correct past errors, would be clearly inappropriate and irresponsible.
Teleological interpretation: Pursuit of general and complet disarmament
The term “object and purpose”, used in Article 60 § 3 b VCLT, is flexible and allows considerations of various types of treaties. In particular its latter element, the “purpose” of a treaty, may encompass aims and goals that can only be reached in the future, even in the far one.
It is suggested here that, in the field of arms control, all efficient measures, in particular contained in treaties, are ultimately aimed at one common goal, namely the realization of “general and complet disarmament”, as has been proposed as early as in the first resolution adopted by the UNGA in 1946, as confirmed later by Article VI NPT and, as a result, a world free from nuclear weapons. In other words, terminating definitively the INF Treaty, a key factor for international security and global stability, based on vague allegations of breach, would cause much more harm for the long and cumbersome fight for a world without nuclear weapons than the actual limited breach does. Again, an issue of proportionality comes up here.
Lack of proportionality
I have suggested elsewhere that this kind of suspension- or withdrawal clause must be considered an exception to the principle of pacta sunt servanda and the stability of treaties. As such, it deserves a narrow interpretation. All in all, it can be argued that the US withdrawal, if based on a material breach in the sense of Article 60 VCLT, is, considering the dramatic potential consequences for the security not only of the USA and Russia, but also of Europe and the entire world, disproportionate and highly problematic, procedurally as well as on the merits and could, therefore, constitute an abuse of the right to terminate the treaty.
In light of what precedes, it is doubtful whether the suspension of the INF Treaty by the USA, followed potentially by definitive withdrawal, is lawful. Two important restrictions on the freedom of the States Parties to terminate that instrument are imposed by the obligation to settle their disputes peacefully, according to the UN Charter, as well as by the duty to conduct negotiations in good faith, in particular in view of a world without nuclear weapons.
Moreover, Articles 60 of the VCLT and XV of the INF Treaty contain a series of important guarantees against a hasty and unreflected termination. The US Government has not yet indicated clearly the legal basis for their measures and, therefore, their suspension “à la carte” does not prove precise enough. As a result, it is not excluded that the unilateral actions of the USA amount to an abuse of the right to suspend/withdraw from the INF Treaty.
If the USA’s termination of the INF Treaty turns out to be unlawful under international law, this could itself be considered a “repudiation of the treaty” within the meaning of Articl 60 § 3 a) of the VCLT, as cited above. This could be used by Russia to suspend the operation of the treaty or withdraw from it too, which it actually announced promptly after the US Government’s declaration. From a legal point of view, however, unless the appropriate procedures have been used by the Parties, the treaty remains in force.
Having said this, could it be argued that the USA and Russia, by their respective declaration of 1st and 2nd February 2019, have lawfully suspended the INF Treaty by mutual consent, as provided for in Article 57 b) of the VCLT? Certainly, treaty parties are the masters of their own treaty and may at any time and contrary to any time-limit or other conditions stipulated by the treaty, agree to suspend or terminate it. Regarding the present situation, however, nothing indicates that between the two parties which are having a genuine dispute over the compliance with the INF Treaty, there has been agreement, even tacit one, on suspension and termination of the instrument, including on modalities and the procedures to follow.
The main value of international law, if interpreted and applied in good faith, lies in the fact that it establishes procedures entailing important limits to the – sometimes arbitrary – behaviour of States, in particular of the most powerful ones. Therefore, it should be taken more seriously in difficult situations such as the current INF Treaty debate, for the sake of our and future generations.
 PhD, Adjunct Professor of International Law and Human Rights Law at Lausanne University (Switzerland) and Suffolk University Law School (Boston MA); member of the International Law Association (ILA)’s Committee on Nuclear Weapons, Non-Proliferation and Contemporary International Law. My thanks go to John Burroughs for his thoughtful comments and suggestions on the text.
 Permanent Court of International Justice (PCIJ), The Mavrommatis Palestine Concessions (Greece v. Britain), Judgment, 30 August 1924, Series A, no 2, para. 19.
 UNGA Res. 2625(XXV), 24 October 1970.
 See e.g. United States Court of Appeals for the Second Circuit, Filartiga v. Pena-Irala,630 F.2d 876 (2d Cir. 1980).
 Case concerning the North Sea Continental Shelf, ICJ Reports, 1969, § 86.
 See, for instance, Article VI § 2 of the CTBT: “When a dispute arises between two or more States Parties, or between one or more States Parties and the Organization, relating to the application or interpretation of this Treaty, the parties concerned shall consult together with a view to the expeditious settlement of the dispute by negotiation or by other peaceful means of the parties’ choice, including recourse to appropriate organs of this Treaty and, by mutual consent, referral to the International Court of Justice in conformity with the Statute of the Court. The parties involved shall keep the Executive Council informed of actions being taken.”
 Ibidem., § 85.
 Mark E. Villiger, Commentary on the 1969 Vienna Convention on the Law of Treaties, Nijhoff, Leiden/Boston 2009, pp. 439-440, referring to the practice of the ICJ, e.g. Legality of Use of Force (Serbia and Montenegro v. Belgium), Preliminary Objections, ICJ Reports 2004, para 100; or LaGrand (Germany v. USA), ICJ Reports2001, para. 99).
 Legality of the Threat or Use of Nuclear Weapons, ICJ Reports 1996, conclusion F).
 Already in 2008, the George W. Bush administration pointed to the flight-testing of a Russian ground-launched cruise missile with an intermediate range between 500 and 5.500 kilometres as a treaty breach (Katarzyna Kubiak, The INF Treaty: The Way Forward, May 2018, p. 2).
 In this sense Daniel H. Joyner and Marco Roscini, “Withdrawal from non-proliferation treaties”, in: Joyner/Roscini (eds.), Non-proliferation Law as a Special Regime – A contribution to fragmentation theory in international law, CUP, 2012, p. 155.
 Ibidem., p. 154.
 Article IV of the PTBT reads as follows: “This Treaty shall be of unlimited duration. Each Party shall in exercising its national sovereignty have the right to withdraw from the Treaty if it decides that extraordinary events, related to the subject matter of this Treaty, have jeopardized the supreme interests of its country. It shall give notice of such withdrawal to all other Parties to the Treaty three months in advance.”
 See, for more details, D.H. Joyner and M. Roscini, Withdrawal from non-proliferation treaties, in: D.H. Joyner and M. Roscini, Non-proliferation Law as a Special Regime, A contribution to fragmentation theory in international law, Cambridge University Press, 2012, pp. 151-171, and D. Rietiker, Le régime juridique des traités de maîtrise des armements, Plaidoyer pour l’unité de l’ordre juridique international, Stämpfli and Bruylant, 2010, pp. 490-509.
 Villiger, op.cit., p. 710.
 This principle derives from the Roman law maxim “ut res magis valeat quam pereat”: It is better for a thing to have effect than to be made void, or in the context of treaties: contracting parties must have had some purpose in negotiating and adopting a treaty, and that it is the duty of a tribunal to ascertain that purpose and do its best to give effect to it.
 Alexander Orakhelashvili, The Interpretation of Acts and Rules in Public International Law, OUP, 2008, reprinted 2013, pp. 555-6.
 Ibidem, p. 556.
 See for the text of the declaration: https://www.armscontrol.org/act/2002_01-02/docjanfeb02
 See R. Müllerson, The ABM Treaty : Changed Circumstances, Extraordinary Events, Supreme Interests and International Law, 50 ICLQ (2001), 508, and J. Rhinelander, The ABM Treaty – Past, Present and Future, 6 JCSL (2001), 91, 103-104. From our point of view, the extraordinary events, referred to in Article 15 § 2 of the withdrawal clause, were not “related to the subject matter of this Treaty.”
 Villiger, op.cit., p. 749.
 Ibidem., pp. 738-9.
 Ibidem., p. 741. Within Article 60 VCLT, only para 2 a), stipulating the right of the innocent parties to react jointly to the breach, provides for a direct action.
 Villiger, op.cit., p. 738.
 Ibidem., pp. 813-4.
 Ibidem., p. 814-5.
 Ibidem., pp. 806-7.
 Ibidem., p. 742.
 Legality of the Threat or Use of Nuclear Weapons, ICJ Reports 1996, para 35.
 https://www.bundeskanzlerin.de/bkin-de/aktuelles/rede-von-bundeskanzlerin-merkel-zur-55-muenchner-sicherheitskonferenz-am-16-februar-2019-in-muenchen-1580936 (our translation from German).
 Villiger, op.cit.., p. 743.
 UNGA Res. 1.I., adopted 24 January 1946, Establishment of a Commission to deal with the problems raised by the discovery of atomic energy. This resolution gives the power to a commission in view of making proposals, inter alia, “for the elimination from national armaments of atomic weapons and all other major weapons adaptable to mass mass destruction” (para 5 c).
 Rietiker, op.cit., p. 571.
 Article 26 VCLT defines this principle in the following terms: “Every treaty in force is binding upon the parties to it and must be performed by them in good faith.”
 Villiger, op.cit., p. 742.
 Article 57 VCLT reads as follows: “The operation of a treaty in regard to all the parties or to a particular party may be suspended: …b) at any time by consent of all the parties after consultation with the other contracting States.”
 Villiger, op.cit., p. 686.