Russia and Eastern Europe

The End of the Open Skies Treaty and the Politics of Compliance

By Alexander Graef
Monday, July 6, 2020, 8:01 AM

On May 22, the Trump administration notified the remaining state parties that the United States would withdraw from the Open Skies Treaty. The treaty has been in force since January 2002 and allows its 34 members to conduct joint, unarmed observation flights over each other’s territory using sensors with a predefined resolution. The U.S. withdrawal will come into effect in November. On July 6, all member states will meet at an online state conference to decide whether to preserve the treaty without U.S. participation.

Why has the U.S. decided to leave the treaty? The main reason is a bilateral conflict with Russia. The official withdrawal statement by Secretary of State Mike Pompeo accused Russia of “flagrantly and continuously violating the Treaty in various ways for years.” Moscow had “twisted and perverted” the treaty’s implementation and even used it as “a tool to facilitate military coercion.” The United States could not “remain in arms control agreements that are violated by the other side, and that are actively being used not to support but rather to undermine international peace and security.” In contrast to the Intermediate-Range Nuclear Forces Treaty, the U.S. did not claim “material breach,” however.

The remaining state parties have reacted cautiously to these allegations. In a common statement, the foreign ministers of 12 member states reaffirmed that “this treaty remains functioning and useful,” and argued that “regarding issues on Treaty implementation” they “will continue to engage Russia … and other European partners to address outstanding issues.” German Foreign Minister Heiko Maas even stated that although “there have indeed been difficulties with respect to implementation on Russia’s part,” they do “not justify withdrawing from the Treaty.”

This begs the question of whether the compliance concerns raised by the U.S. administration vis-à-vis Russia are justified and, if so, on what grounds.

Assessing treaty compliance is difficult, because the indeterminacy of legal provisions enables governments to use norm-based arguments strategically. This is particularly the case in international law. States use the absence of a sovereign legislature and judiciary to draw on political arguments concealed by legal rhetoric. They justify their interests on the grounds of allegedly common and uncontested standards of legitimacy. The Open Skies Treaty adds another challenge: Secrecy around the treaty has limited the public’s ability to make informed judgments about the degree of legal deviation and its severity.

Even the annual compliance reports published by the U.S. State Department acknowledge normative ambiguity, arguing that “concerns relating to compliance involve matters of interpretation.” State actions that give rise to concerns can either “constitute violations or simply represent differences in implementation approaches or some other permissible activity.” Over time the wording of the compliance reports, however, has changed in subtle but significant ways. From 2005 to 2017 the unclassified versions of the reports did not formally find Russia “in violation” of the Open Skies Treaty or its provisions. Instead, they accused Moscow of failing “to meet [its] Treaty obligations” and being not in compliance with its obligations[,]” or they expressedserious compliance concerns[.]” The tone changed suddenly in the 2018 report, the first one solely prepared and published by the Trump administration. How can we explain this shift in wording?

To understand the underlying politics, we need to take a closer look at the four allegations as cited by Pompeo in his withdrawal statement. They fall into three categories: flight safety, territorial status conflicts and national security.

Flight Safety

Disputes about compliance have been a constant feature of the Open Skies Treaty since its inception. Most contested measures, as the U.S. State Department puts it, “can largely be attributed to different interpretations and understandings of various Treaty provisions.” Some are trivial and even arcane, for example, controversies about the feasibility of overflights during national weekends and holiday periods; others have limited full territorial observation on the grounds of national safety and air traffic control regulations. The Open Skies Treaty itself knows no such limits, however. It allows observing the entire area of a state’s territory, including flights through hazardous airspace. The treaty cites flight safety as an exception to this rule, but only in connection with bad weather.

As a result, flight safety concerns regularly cause disputes. Over time, member states have learned to settle some of them successfully within the Open Skies Consultative Commission (OSCC), including long-standing issues between Russia and the U.S. In April 2016, Russia lifted altitude restrictions over Chechnya. Similarly, in 2016, the U.S. finally granted access to all its island territories, which Russia had repeatedly asked for. In June 2017, Russia stated that it would no longer impose airspace restrictions during the presence of VIPs (presidential envoys). There have also been debates about altitude restrictions for flight safety over the Moscow city center. It has turned out, however, that imposing altitude restrictions over national capitals is common practice in many member states. Altitude restrictions in general are now being addressed (by the OSCC) as part of a broader discussion about air traffic control procedures.

Military Exercises and Kaliningrad

Two compliance concerns related to flight safety measures remain. The first involves restrictions during Russia’s strategic Tsentr military exercise that happens every four years. In September 2019, Russia denied a joint U.S.-Canadian team a previously agreed-upon second flight segment over the exercise, citing flight safety as the reason. Attempts to find agreement on alternative flight paths were unsuccessful.

The second concern, which revolves around a 500 km limit for flights over the Kaliningrad region imposed by Russia since June 2014, is a more complicated issue. According to the Russian Ministry of Foreign Affairs, the reason for this measure had been a Polish overflight in April that year, which took an unusually lengthy path over the small region. Itsalleged zigzag route had reportedly caused chaos with air traffic control and limited civilian air travel. The controversy is not about whether a separate limit for flights over the Kaliningrad region is justified in general. This is indeed possible, but only for flights originating from the newly designated Open Skies airfield in Khrabrovo located in the region, which since 2014 functions as a new point where observation flights may start or end. Instead, the question is whether the treaty allows establishing sublimits for flights from already established Open Skies airfields such as Kubinka, near Moscow. The treaty allows establishing different limits for territories separated from the mainland to ensure “effective observation” (Annex E), on two conditions: if the territory is separated by more than 600 km, or if it is located beyond 35 percent of the maximum flight distance from a designated Open Skies airfield. Neither rule applies to the Kaliningrad region. A decision by the OSCC from March 2004 further specifies that states shall neither “increase the number of flights required for the opportunity to observe the entire territory” nor decrease the maximum flight distance of already established airfields.

Russia is stretching the wording of the treaty, pushing the limits of accepted rules to their breaking point. Moscow holds that the number of flights to observe Russia’s entire territory has not changed; efficient observation of the Kaliningrad region would be possible and the maximum flight distance from Kubinka (5,500 km) remained essentially the same even with a sublimit in place. Russia is also relying on practical arguments, suggesting that the 500 km limit would be sufficient to cover 77 to 98 percent of the Kaliningrad region’s territory per flight. Although this might be true, such concerns provide no grounds for the establishment of sublimits.

Territorial Status Conflicts

A second set of concerns involve territorial status conflicts. These are more problematic, because they are unrelated to the treaty. For example, since 2002 Turkey has consistently vetoed the accession of the Republic of Cyprus, an EU member state, to the treaty, because Ankara does not recognize Cyprus’s sovereignty. In 2005, the unsolved issue prevented the adoption of the final document at the treaty’s review conference, because Turkey objected to a statement that described the accession of Cyprus as pending. From January 2011 to July 2013, the normal proceedings of the OSCC were interrupted, because Greece insisted on putting Cyprus’s membership on the agenda, to which Turkey, again, refused to give its consent. Another issue in the same category is the status of the Crimean peninsula. In 2014, Russia invited other parties to overfly the territory from a designated Open Skies refueling airfield. Since the other state parties continue to view Crimea as part of Ukraine, the peninsula remains practically outside of treaty provisions.

Georgian-Russian Border

Russia’s denial of observation flights within a 10 km corridor along its border with Georgia is similar in kind. It stems from a territorial conflict about the political status of two Georgian breakaway regions, Abkhazia and South Ossetia. Russia recognized the sovereignty of both regions in the aftermath of its war with Georgia in August 2008. In light of this recognition, Russia sees as applicable Article VI of the Open Skies Treaty: “[T]he flight path of an observation aircraft shall not be closer than … ten kilometers from the border with an adjacent State that is not a State Party.”

No member state of the Open Skies Treaty shares this position. To them, Abkhazia and Ossetia are de jure Georgian territories. Hence, the article cited by Russia does not apply. Georgia regards the Russian position as a violation of its own sovereignty. Nevertheless, even after the war in 2008, both states continued to conduct overflights over each other’s territory, each time with the U.K. as a flight partner.

In April 2012, Georgia informed the state parties that it would cease performing its obligations vis-à-vis Russia under the treaty. It stopped its own flights over Russia and the latter has not been able to conduct flights over Georgia in turn, although it has continued to request such flights during the annual flight quota negotiations.

From a purely technical point of view, the 10 km limit imposed by Russia on its border is less problematic than it might seem. Given a sufficiently high altitude and good weather conditions, panorama cameras used by the U.S. (with a swath width of more than 20 km) can take images beyond this distance.

Nevertheless, the dispute has had significant effects on the treaty. At the quota negotiations in October 2017, Russia made a successful bid for a flight over Georgia, which led Tbilisi to withhold its consent to the full package of quota distribution. The lack of consensus made regular flight missions for all member states in 2018 impossible. At the negotiations in October 2018, Russia did not file a request for an overflight, and flights resumed in 2019. The underlying problem, however, has not yet been solved.

National Security

The third category of concerns pertains to perceived threats to national security. Such concerns go beyond the treaty’s normative framework, because they question its very purpose as an instrument of trust- and confidence-building. Instead of compliance with (contested) treaty provisions and their practical application, the issues at stake are political power and the treaty’s conceptual validity.

When President George H.W. Bush revived Eisenhower’s original idea of Open Skies in May 1989, he argued that “such unprecedented territorial access would show the world the true meaning of the concept of openness” and could reveal the Soviet Union’s commitment to change. From the outset of negotiations, one major concern was to strike the right balance between the openness necessary for confidence-building and national security.

The possible implications of this trade-off between transparency and security were also discussed in the U.S. Congress upon ratification. In its report on the “Intelligence and Security Implications of the Treaty on Open Skies” from May 1993, the Senate Select Committee on Intelligence found that “little or no sensitive defense information is likely to be compromised by Open Skies flights.” The committee further argued that “limits on sensor resolution, combined with required delays between submission of a mission plan and the beginning of a limited observation period, effectively limit any country’s ability to gain sensitive information from overflights of the United States or U.S. facilities overseas.” In terms of this view being true, not much has changed since.

Targeting Critical Infrastructure

Nevertheless, since 2016, an increasing number of anonymous administration officials and intelligence officers has publicly expressed worry that Russia could be using Open Skies imagery to target U.S. critical infrastructure. In February 2016, the head of the Defense Intelligence Agency, Lt. Gen. Vincent Stewart, suggested that by using digital techniques Russia would “get incredible foundational intelligence on critical infrastructure, bases, ports, all of our facilities.” Around the same time, USSTRATCOM commander Adm. Cecil Haney warned that “the treaty has become a critical component of Russia’s intelligence collection capability directed at the United States.” Considering that the allowed maximum sensor resolution and the general rules for mission planning have remained the same since 2002, these statements came as a surprise. All state parties, including the United States, have welcomed the ongoing transition from analogue, black-and-white film to commercial digital aerial cameras.

Hence, Pompeo’s statement about the Russian use of Open Skies imagery “in support of an aggressive new … doctrine of targeting critical infrastructure in the United States and Europe with precision-guided conventional munitions” must be taken with a grain of salt. Given the standardized, limited resolution of Open Skies sensors and established procedures for data processing, the idea that Moscow would receive valuable information for targeting critical infrastructure seems far-fetched. Nevertheless, the fact that these and similar allegations are made at all speaks to the lack of trust between both states. Since public verification of classified data is impossible, such claims ultimately become questions of belief and reinforce existing political sentiments.


The sublimit over Kaliningrad, the denial of observations in the border area to Georgia, and conflicts about national safety regulations are problematic and legitimate grounds for critique. However, they do not diminish the overall practical value of Open Skies missions, whose “vast majority,” as the State Department acknowledges, “occur without incident.” For European member states, the treaty is important for both intelligence collection and confidence-building. Allies also consider the recent, tentative steps to address compliance issues by Russia.

In March 2018, Moscow signaled that it would resume “receiving observation flights in 10 kilometers contiguous to two sections of Russia’s state border in the Caucasus” and make them permanent under the condition “that Georgia implements in good faith its obligations to accept Russian observation missions.” Likewise, in February 2020, Russia allowed a joined flight by the U.S., Lithuania and Estonia with a range of 505 km over the Kaliningrad region, thereby undermining its own long-held policy. It is unclear whether this was done to buttress public justification efforts in the wake of an expected U.S. withdrawal or whether it represents a genuine sign of goodwill. Time will tell.

By contrast, treaty opponents in the U.S. have used legitimate compliance concerns to argue that Russia has, as Pompeo puts it, “weaponized the Treaty by making it into a tool of intimidation and threat.” They have thus succeeded in transforming compliance issues into matters of national security. As we know now, this strategy has been politically effective. The U.S. withdrawal from the treaty reflects both the very poor bilateral relations with Russia and President Trump’s contempt for the international liberal order. It also illustrates the limits of using cooperative international law in times of perceived great power competition. Given the supreme quality of U.S. national technical means, the Open Skies Treaty has always been more about Washington’s foreign policy leadership and global diplomatic engagement, including alliance politics, than about the collection of additional intelligence. However, to the current U.S. administration, these objectives seem to be elements of a bygone era.