Established in the wake of the Cold War, the Open Skies Treaty has provided the United States, Russia, and dozens of other countries in Europe with reassurance regarding each other’s intentions and capabilities. Signed in 1992 and entering into effect in 2002, the treaty provides for overflight rights by surveillance aircraft on short notice over the territory of the signatories. These overflights help the signatories identify deployments of military equipment and infrastructure, thus providing early warning of impending attack and transparency with respect to military buildups. Together with a raft of other treaties (including the Intermediate-Range Nuclear Forces Treaty (INF), New START, and the Conventional Forces in Europe Treaty (CFE)), Open Skies helped create an architecture for managing security concerns in post-Cold War Europe.   

Recently, however, the treaty has come under attack from opponents within the United States. Other parts of the security architecture have already fallen away, including the Anti-Ballistic Missile (ABM) Treaty, the CFE, and most recently the INF. Every arms control agreement crystallizes a particular strategic and technological reality, and not every agreement can survive geopolitical and technological changes. The Open Skies Treaty, however, represents a low-cost answer to an age-old problem of international security, providing a mechanism for monitoring deployments of military forces and providing assurance to vulnerable nations. Discarding the treaty would represent a surrender to anti-arms control fetishism, rather than to a careful assessment of the security interests of the United States.

The unarmed observation aircraft approved for Open Skies overflights are equipped with cameras for photo and video collection, synthetic aperture radar (SAR), and infrared sensors--all of which are calibrated to allow analysts to scan for changes in infrastructure or the buildup of various military equipment, but low enough resolution to avoid divulging any sensitive information. Critics argue that the constellation of higher resolution satellites the United States now has in Low Earth Orbit renders the Open Skies Treaty obsolete. Though analysts debate whether the data collected is replicative or complementary to that sourced through spy satellites, some argue that the shorter warning times and flexible flight paths of Open Skies flights offer an advantage to the predictable orbit of satellites.  

Perhaps more valuable than any actual intelligence gathering that directly impacts U.S. national security decisionmaking, the treaty provides for valuable intelligence sharing between each of the 34 signatories, most of which are U.S. allies, and many of which would otherwise be unable to acquire such intelligence. Once each overflight is completed, copies of all data and images gathered are made available for purchase to each of the signatories. Smaller-GDP countries uniquely benefit from the intelligence gathered in these overflights, as they may not have their own satellites in orbit or may not be able to afford their own surveillance aircraft. As Amy Woolf from the Congressional Research Service notes, “while the United States might share its concerns about military activities with other nations in Europe, it is unlikely to share highly classified satellite images or data.” Over 1,500 overflights have been conducted since 2002.   

Open Skies supporters also point to the treaty as an opportunity for the U.S. to demonstrate resolve and support for its allies. In 2014, when Russia was quietly amassing forces at the border and sending “little green men” into Ukraine, Kiev requested an overflight of its own territory, something rarely seen but provided for under the treaty under certain circumstances as an “extraordinary observation flight”. The U.S. and Ukraine jointly conducted this overflight of the region, allowing the U.S. to publicly reaffirm its commitment to the alliance. Again, in December 2018, when Russia seized three naval vessels in the Black Sea, a joint “extraordinary observation flight” was conducted. In both of these cases, the imagery gathered from this overflight, which confirmed Russia’s illegal, unprovoked actions in the region, was then made available to each of the treaty signatories.  

Supporters argue that the treaty is most valuable in the ways it provides transparency and promotes stability. In addition to providing timely intelligence to allies about changes in infrastructure or deployments, the treaty connects the U.S. and Russian militaries and creates an opportunity for dialogue and confidence building. For each Open Skies flight, observers from both the host country and the intelligence-gathering country are present together in the aircraft, with crews working closely together in the days surrounding the flight. With increased tensions and few other avenues for U.S.-Russian connectivity, treaty supporters contend that the value of such military-to-military interaction has only multiplied since the treaty was signed at the end of the Cold War. Moreover, these connections themselves provide the opportunity for intelligence gathering. The very process of operating aircraft out of Russian bases gives Americans a sense of how those bases work, of the nature and number of the personnel who work at them, and a host of other tactile, local knowledge that satellite photographs cannot replicate.    

Open Skies critics argue that Russia benefits more from the treaty than the United States. Much like the INF treaty, Russia has engaged in minor violations of the treaty, restricting overflights of both Georgia and Kaliningrad. The former complaint regards a dispute over Russia’s definition of the border, while the latter involves Russian recalcitrance about surveillance of one of its most heavily militarized regions (Russia argues that it limits Kaliningrad overflights to a 500 km range because of an air traffic accident caused by a “2014 Polish overflight that interfered with commercial aviation”). The United States has responded in kind with restrictions to overflights of Alaska and Hawaii. Critics also argue that the United States has more powerful space surveillance capabilities than Russia, meaning that Russia gains disproportionately from overflight rights. Additionally, treaty critics contend that Russia’s aircraft-based optical sensors are more advanced than those of the United States, giving Russia even more of an advantage.  But it should be noted that the sensors Russia uses are in compliance with the treaty’s limits, as capabilities must be approved by consensus from signatories, and all aircraft sensors are thoroughly inspected by the implementing body before being authorized for flights. Therefore, any slight or perceived advantages seem to have resulted from Congressional unwillingness to upgrade U.S. sensor technology and improve the readiness of surveillance aircraft, a resistance manufactured by treaty foes. Finally, critics point to Russia’s pattern of deception in some of the other treaties that constitute to post-cold war security architecture. 

Behind all of these specific complaints lurks another concern. Many in Congress and the Administration (as well as former National Security Advisor John Bolton) are skeptical that bilateral and multilateral arms control agreements are able to effectively address post-Cold War security concerns, viewing such agreements as ill-advised concessions to adversaries, tying the hands of U.S. decisionmakers rather than offering real national security benefits. Alarmist headlines covering Open Skies flights (such as “Russian aircraft overflying United States”) exacerbate this concern.  

Generally speaking, arms control agreements should collapse when the strategic or technological foundations that underlay the agreement have collapsed.  There is little reason to believe that this condition holds today with respect to the Open Skies treaty. The strategic logic of the agreement- to increase transparency between the United States and Russia- remains wholly sound, and indeed is perhaps stronger today than it was two decades ago.  Intelligence sharing arrangements with allies continue to provide useful assurance regarding capabilities and intentions on either side. The treaty does not leave either of the two primary signatories at stark disadvantage relative to one another, or to any third country. Though, the U.S. should continue to address specific concerns about Russian violations in cooperation with the implementing body, the Open Skies Consultative Commission (OSCC). With respect to sensors, technology has changed dramatically in the last thirty-five years, but not to the degree that overflights fail to provide new, useful information.  The specific balance of technology may slightly benefit either the United States or Russia, but not beyond a degree of resilience built into the treaty.   

Looking into the future, the United States needs to think about what the next round of arms control agreements will look like.  Hawks tend to think that the rise of China, India, and others means that the current treaty architecture should be tossed in the garbage.  In some cases (arguably the INF) this may be true, but in others (New START) discarding existing arrangements in the futile hope of restricting future Chinese growth would be absurd to the point of disaster.  The Open Skies treaty falls into this latter category, and provides a foundation for at least thinking about how China, India, and others might be brought into regimes that enhance transparency.   

Mary Chesnut is a program manager at the Nuclear Security Working Group (NSWG), a nonpartisan organization at the George Washington University. Mary has an MA in National Security Studies from the University of Kentucky’s Patterson School of Diplomacy and International Commerce, and a BA in Russian from Rhodes College. The views reflected in this article are the authors’ alone and do not reflect the views of any of the institutions mentioned above.