Non-compliance and disputes between Russia and the US resulted in the US exiting the Open Skies Treaty. If Russia withdraws in response, European countries will lose an important source of intelligence.

The Open Skies Treaty (OST), which was signed in 1992 and came into force in 2002, is one of the arms control treaties signed at the end of the Cold War. After the US exited in May, the treaty has been ratified by 33 countries from North America and Europe, including Russia.

The treaty allows signatories to conduct an observation flight with an aircraft equipped with sensors over the territory of another State Party with 72-hour notice. Flights can be used to monitor military instalments and manoeuvres, which reduces tensions by making the military activities of signatories more open.

In a trust-building measure, officers of both parties can be on board the flight and the imagery is made available to other State Parties. The equipment is also certified by State Parties. In total, over 1,500 flights have been conducted since the treaty came into force. Finland also conducts flights every year, particularly to Russia.

The US and Russia both possess reconnaissance satellites, so flights are not as significant to them as they are to countries without satellites of their own. The most significant advantage of the treaty is transparency: Information about anomalous military activity can be shared openly.

During the first phase of the war in Ukraine, State Parties conducted 22 flights over Russian territory, which allowed the observation of Russia’s military activity during the crisis. The US also conducted a flight in 2018 in order to support Ukraine after Russia captured a Ukrainian ship and its crew. Information provided by satellites cannot usually be used in a similar manner because it is important to keep their capabilities secret.

By withdrawing from the treaty, the US gave up the possibility of supporting its partners by conducting observation flights. The US justified its exit by accusing Russia of restricting flights allowed by the treaty and using Open Skies imagery to plan possible strikes on the critical infrastructure of other State Parties.

The problems associated with the OST have intensified in recent years. Russia has restricted flights during a military exercise and over strategically important Kaliningrad. The US restricted Russia’s flights in response, to which Russia responded with its own restrictions. The certification of sensors has also led to disputes. Russia has also restricted flights near its border facing the Georgian regions of South Ossetia and Abkhazia, which Russia recognized as independent, and claimed that the OST thereby requires it to prevent flights over this area.

The US has not published the evidence regarding the targeting of infrastructure. However, US military and intelligence officials have also voiced concerns about the issue in the past. Russia has likewise accused the US of filming its civilian infrastructure.

Russia’s compliance with international arms control treaties has become even more selective since 2014, and the same applies to the OST. Russia usually denies contractual violations or offers negotiations, wanting something in return. For instance, Russia has linked the flights near its Georgian border to the right to conduct flights in Georgia, which were banned in 2012 due to Russia’s actions.

Russia has also restricted observation flights due to its strategic aim to conceal its actions, knowing that the West desires transparency, which is why it will not provide it for free.

Russia also designated an OST refuelling airfield in Crimea. By participating in a flight to Crimea, representatives of the West could be interpreted as recognizing that the territory is part of Russia. Russia has persistently tried to draw foreign representatives to Crimea on different grounds, and utilized the treaty to support this goal immediately after it annexed Crimea illegally in 2014.

The OST was designed to build trust, but it has been used to erode it. In a situation where great powers consider each other competitors and the treaty has been violated before, restrictions on flights that could have been acceptable in other conditions may have been considered serious violations. The OST provides negotiating tools, but it cannot mitigate the conflict at the heart of great power relations.

The US exit was also motivated by the belief shared by some influential Republican politicians and officials that many treaties which restrict the actions of the US are against its national interests. This trend has intensified in recent years, and the US has withdrawn from several treaties with no regard for the consequences of its exit for its allies and partners. Before the US exit from the OST, some American decision-makers questioned why Russia was even allowed to conduct observation flights.

Opinions were divided over the issue in the US, and there was also support for remaining in the OST. In a situation where the US sees Russia as an adversary even more clearly and actors who hold a critical view of multilateralism are in power, the perception of national interests weighed more heavily in the balance than the option to support allies and partners.

The OST is still in force, but Russia may withdraw from the treaty or respond to the US exit in other ways. Russia’s withdrawal from the treaty would increase uncertainty in Europe, and NATO members would be even more dependent on the intelligence provided by the US. Moreover, non-NATO countries would permanently lose a significant source of intelligence. Replacing the OST with another treaty would be very difficult in the conditions of the ongoing great power competition. Even in the agreeable post-Cold War days of the 1990s, the ratification round of the OST took ten years.