The Treaty on Open Skies in the Face of Withdrawals

[Maria Xiouri is a Lecturer in Law at the University of Bedfordshire. Her book The Breach of a Treaty: State Responses in International Law was published by Brill in March 2021.]

On 22 May 2020, the US submitted a notice of its intention to withdraw from the Treaty on Open Skies (‘OST’) to the Treaty Depositaries and to all other States parties to the Treaty (33 in number, excluding the US), pursuant to its Article XV(2). Such withdrawal is effective six months following the date of the notification. The OST, concluded at Helsinki on 24 March 1992 and entered into force on 1 January 2002, is a multilateral treaty allowing for the conduct of unarmed observation flights by States Parties over the territories of other States Parties to ‘improve openness and transparency, to facilitate the monitoring of compliance with existing or future arms control agreements and to strengthen the capacity for conflict prevention and crisis management…’ (see paragraph 6 of the Preamble to the Treaty).

Art XV(2) of the OST does not provide a specific ground for withdrawal. The US claimed that the reason for its withdrawal was that it was no longer in its interest to remain party to the OST, allegedly because the Russian Federation had ‘flagrantly and continuously violated the Treaty in various ways for years’. Alleged Russian breaches include flight limitations over Kaliningrad and the restriction of flights in Russia near its border with Georgia. Interestingly, according to the US, the Russian breaches went ‘beyond just violating the Treaty’s provisions themselves’ and ‘fatally undermined the very intent of the Treaty as a confidence- and trust-building measure’ (see here and analytically here, pp. 53-6, emphasis added). The aforementioned statement seems to echo the dictum of the International Court of Justice in the Nicaragua case. In that case, the Court accepted that there were certain activities of the US which were ‘such as to undermine the whole spirit’ of the treaty between the US and Nicaragua (Nicaragua [275-6]). However, the Court also clarified that ‘There must be a distinction, even in the case of a treaty of friendship, between the broad category of unfriendly acts, and the narrower category of acts tending to defeat the object and purpose of the Treaty. That object and purpose is the effective implementation of friendship in the specific fields provided for in the Treaty, not friendship in a vague general sense’ (Nicaragua [273], see also the Dissenting Opinions of Judges Schwebel [253]; Oda [80] and Sir Robert Jennings (p. 542)).

It must be noted that even if the US had implied that Russia had materially breached the OST, the definition of material breach according to the letter of Art 60(3)(b) of the 1969 Vienna Convention on the Law of Treaties (‘VCLT’) requires that the object and purpose of a treaty is defeated through the breach of specific provisions of that treaty (‘A material breach of a treaty…consists in…(b) the violation of a provision essential to the accomplishment of the object or purpose of the treaty’). Of course, the US might have also implied that the Russian violations were extraordinary events, related to the subject matter of the Treaty, which had jeopardised the supreme interests of the US (a common ground for withdrawal stipulated in disarmament treaties, although such a ground is not stipulated in the OST).

In any event, the US claimed that it (as well as other States parties) had raised its compliance concerns repeatedly in various interactions with Russia and stated that it would reconsider its intention to withdraw if Russia returned to full compliance with the OST. On its part, Russia denied that it had breached the OST and claimed that it was the US that had committed breaches of the OST (see here and here). According to Russia, the real reason behind the US withdrawal was ‘the…US administration’s negative attitude towards arms control in general and, in particular, to the arms control agreements signed by previous administrations’ (see here).

Regarding reactions from other States parties to the Treaty, a joint statement was issued by twelve EU Member States expressing regret over the US withdrawal from the OST. The implications of the US withdrawal from the Treaty were also discussed in a Conference of States Parties to the Treaty convened by Canada and Hungary, as the Depositaries of the OST, on 6 July 2020, pursuant to Article XV(3) of the Treaty.

Interestingly, the US withdrawal also presents problems as a matter of US domestic law (for analysis see also Jean Galbraith, ‘United States Gives Notice of Withdrawal from Treaty on Open Skies’ (2020) 114: 4 AJIL 779-84).

The US withdrawal took effect on 22 November 2020. The Foreign Ministry of the Russian Federation initially issued a relevant statement, in which it stated that it would remain a party to the OST only if the other States parties provide legal guarantees that they will enable observation over their entire territories, including US military sites in Europe, and that they will refrain from transferring observation data to non-parties to the Treaty, such as the US. According to Russia, the OST does not contain relevant express provisions, and a relevant decision of the Open Skies Consultative Commission adopted in 2002 is inadequate due to its general formulation.

It is worth examining more closely one of the breaches of the OST by the Russian Federation. Russia has refused to allow access for Open Skies observation flights in certain areas since 2011, including within 10 kilometres of the border with the regions of South Ossetia and Abkhazia. It has justified its refusal on the basis that Art VI, Section II(2) of the OST prohibits flights within 10 kilometres of a State which is not party thereto and claiming that the above mentioned regions are independent States not parties to the OST. Nevertheless, South Ossetia and Abkhazia are considered by all other States Parties to be part of Georgia, which is a party to the OST. In response, since April 2012 Georgia has not permitted Russian Open Skies overflights of Georgian territory as a countermeasure. Russia has claimed that the Georgian act is ‘a clear and gross violation of the key OST provision’, obviously denying its own breach of the OST, which justified the non-performance by Georgia of its obligations under OST towards Russia as a countermeasure under Articles 22, 42 and 49 of the 2001 ILC Articles on the Responsibility of States for Internationally Wrongful Acts.

It can be observed that the responses by the US and Georgia to the breaches of the OST by Russia consisted in withdrawal from the Treaty and countermeasures respectively, and not in responses to the breach of a treaty under Art 60 VCLT, namely termination or suspension (with regard to the US, to the extent that Art 60 constitutes customary international law, as the US is not a party to the VCLT). This highlights the limitations of Art 60 VCLT, under which the only individual response available in case of breach of a multilateral treaty, such as the OST, would be the suspension of its operation, which was presumably not considered by both States as a desirable response, quite apart from the fact that the conditions of application of Art 60 VCLT, including the proof of the material character of the breach, are much stricter (see indicatively Bruno Simma and Christian J Tams, ‘Article 60’ in Olivier Corten and Pierre Klein (eds), The Vienna Conventions on the Law of Treaties, A Commentary (OUP 2011) 1351). Besides, it is doubtful that the suspension of the operation of a treaty is an effective response to its breach (see Maria Xiouri, The Breach of a Treaty: State Responses in International Law (Brill/Nijhoff, 2021).

In any event, Russia claimed inter alia that the US withdrawal ‘essentially destroyed the balance of interests of the State-Parties reached when the Treaty was signed’ (Russia has noted that the US participation in the OST was a major condition for the ratification of the Treaty by the former in 2001), and, claiming that the other States parties to the OST refused to provide the above mentioned legal guarantees on the basis that such a provision is already included in the Treaty, declared on 15 January 2021 that it would begin the domestic procedures for its withdrawal from the OST, upon the completion of which it will send the relevant withdrawal notification to the Treaty Depositaries.

It was hoped that Russia would resume compliance with its obligations under the OST and that the US would again become a party to the OST under its new administration, since the Treaty enhances transparency and security across the Euro-Atlantic area. There was relevant communication between the US Secretary of State and the Russian Minister of Foreign Affairs (see here and here); however it seems to have been unsuccessful, since the US has announced that it is not returning to the OST and Russia is continuing the withdrawal process (see here, here and, more recently, here). In fact, on 19 May 2021 Members of the State Duma adopted a bill ‘On denunciation by the Russian Federation of the Treaty on Open Skies’, which has been signed by the Russian President, and, on 18 June 2021, Russia sent notification of its decision to withdraw from the OST to the Treaty depositaries and to the other States parties to the Treaty; moreover, it requested the Treaty depositaries to convene 30 days following the notification a conference of the States parties in order to review the consequences of Russia’s withdrawal. The withdrawal will take effect on 18 December 2021. It seems, therefore, that the opportunity to preserve an important treaty such as the OST— the future of which becomes uncertain following the withdrawal of two key States parties— and to reverse the recent trend of withdrawals from treaties, which prejudices treaty stability, has unfortunately been missed.