A2/AD threat rings

Russia’s A2/AD strategy is a myth

This post contains a paper I wrote for the MAST Northern Coasts 2019 conference in Copenhagen on 4-6 September 2019. It is a stark criticism of the idea of A2/AD and in particular the almost hysterical application of threat rings that is common in Western defense discussions.


The paper examines Russia’s sea denial capabilities in the Baltic region. It is often described as if Russia has the ability to close the Baltic Sea for Western navies. This is a vulnerability for NATO because it could be impossible to reinforce the Baltic States in case of a war. However, recent research indicates that the effectiveness of Russia’s so-called A2/AD capabilities is overrated. There are significant weaknesses in Russia’s surveillance and missile technology, and NATO can explore these opportunities.

This paper expands on that argument. It is shown that Russia would face both technical and political obstacles to the establishment of effective sea denial in the Baltic Sea. The technical argument is that Russia does not have the necessary naval or air assets to deny the access of Western navies to the Baltic Sea for very long. The political argument is that it is unsustainable for Russia to block all maritime traffic in the Eastern Baltic, because such a move would be counterproductive and make it less likely that Russia could achieve their political goals.

A short discussion suggests that A2/AD should rather be understood within the framework of layered defense systems. This focus rejects the notion of impenetrable bubbles, and consequently it discredits the idea that Russia intends to use A2/AD as a tool to secure offensive victories.


The military concepts of Anti-Access and Area Denial have received much attention in the last decades. While there technically is a distinction between the two concepts, they more or less cover the same thing and are usually merged in the common abbreviation “A2/AD”.

The central notion is that modern missiles and surveillance technology make it possible to turn large areas into impenetrable fortresses.1 The cornerstone in such an A2/AD system is typically long-range ground-launched missiles, and if an adversary’s ship or aircraft shows up, it can easily be defeated at great distances. Obviously, the adversary may also have long-range missiles, but the defending party has a tremendous advantage: Easy target acquisition. One side is forced to operate ships or aircraft in an open environment, whereas the other can base his missiles on trucks that can move around and hide in the terrain.

Russia’s ability to establish effective A2/AD has been widely discussed. Often, the metaphor of bubbles is applied, and they translate into illustrative threat rings on a map.2 This can provide some frightening graphics, because commonly the sizes of the bubbles are depicted as the maximum range of the longest shooting missile. For air defense missiles the number 400 kilometers is often used because it is the theoretical maximum range of the longest shooting missile that the S-400 missile system can operate. For anti-ship missiles the range is often mentioned to be around 300 kilometers because that is the possible range of an Oniks missile fired from a Bastion coastal defense system.3 This can give the impression that Russia can effectively deny access for any ship or aircraft within hundreds of kilometers from the location of these missiles.4

A2/AD threat rings
Some threat rings on a map. I even put a missile battery in Estonia.

The flaws in this approach are significant. First, the operational range of a missile is substantially smaller than its maximum range. This comes from the fact that the missile never actually flies in a straight line but needs to adjust its movements to hit the target. Also, the missile almost always follows a sub-optimal flight trajectory because that allows it to be resilient against countermeasures. Second, the threat rings only represent the weapon range and don’t take the difficulty of target identification and acquisition into account. The hard part is not so much to shoot, but to know what to shoot at. This requires sensors and communication systems that possess much less impressive characteristics than the traditional notion of an A2/AD bubble would imply.

A recent report from the Swedish Defence Research Agency has shown that Russia is far from able to close the Baltic Sea in case of an armed conflict. In fact, the study finds that the effective range of the S-400 air defense system may be as little as 20-35 kilometers against a low-flying opponent.5 If the threat rings are drawn with such modest ranges in mind, the map of Russian A2/AD bubbles in the Baltic Region looks much less impressive.

Technical limitations to Russia’s sea denial capabilities in the Baltic

Sea denial can be understood as a subcategory of A2/AD. It means that you prohibit an opponent from using the sea to achieve his goals. For simplicity’s sake I will here limit that discussion to a question of excluding NATO from operating in the Eastern Baltic Sea with surface ships. Expanding on the argument that the hard part of A2/AD is to maintain situational awareness in the area that you are trying to control, I will examine Russia’s abilities to establish sea denial in the Baltic Sea.

In this section I look at the technical side of the matter. It is a very brief overview, and the essential point is that Russia does not have the sufficient capabilities to establish sea denial for a prolonged period of time. In the next section I complicate matters further by adding a political layer of considerations.

Land-based radars

The most obvious tool for Russia to monitor ships on the Baltic Sea may appear to be land-based radars. After all, Kaliningrad is situated in a forward position, so one could get the idea that there would be good coverage over most of the central Baltic from the enclave. That is not the case. The curvature of the earth means that ships must be really close to shore in order to be spotted on a land-based radar. Even if the radar is placed 100 meters above sea level, it will still only spot a large warship like a frigate on distances of about 60 kilometers (35 nautical miles). This is nowhere near enough to create a sufficient picture of the maritime space. Furthermore, such a land-based radar is an easy target for an anti-radiation missile, so there is little reason to believe that it would exist for very long.


Another option is to use submarines for target identification and dissemination. The Baltic Sea provides good conditions for coastal submarines because different bodies of water meet to create a complex operating environment with intermingling hydroacoustic layers of temperature and salinity. It is therefore easy for a submarine to hide in the Baltic Sea. The trouble is that submarines are not particularly good at monitoring surface traffic. They cannot operate radar, and their visual range is limited by a very low eye height. With passive sonar they can detect surface ships at greater distance, but that is a technology with varying reliability. Furthermore, the submarine is vulnerable to anti-submarine measures, so it can be difficult to get close enough to the surface ships. Finally, it is really hard to communicate between the submarine and shore. If they transmit anything on traditional radiocommunications, they give away their position and warn the potential target. Satellite communications give some protection against detection, but it still leaves the submarine in a vulnerable position while reporting on the target.

In other words, a submarine is not a good tool for coordinating attacks with land-based missile batteries. It can – of course – use its own weapons to engage a target, but that does not solve the problem of how to provide target data for the land-based missiles. Furthermore, Russia currently only has one operational submarine in the Baltic Fleet.6

Surface ships

Surface ships are valuable in maritime surveillance because they can provide close-up verification of a target’s identity, but they are not particularly good at monitoring large spaces of water. Because of the curvature of the earth, a surface search radar on a frigate only covers about 40-50 kilometers. In order to benefit from the long range of the coastal missile batteries, Russia would have to station the surface scouts in a forward position where they would be extremely vulnerable.

Airborne platforms

Aircraft are good surveillance platforms. Their speed makes them flexible, and the high altitude means that they achieve a good range. For the sake of simplicity, I will only cover two types of aircraft here, namely dedicated AWACS aircraft (Airborne Warning and Control System) and unmanned surveillance drones.

Russia is in the process of developing a new AWACS aircraft by the designation of Beriev A-100. It will supposedly be operational next year, and it will replace the aging Beriev A-50. Both of these aircraft are able to spot large surface warships at large distances. According to Jane’s, they can see a warship with a radar cross section of 250 m2 at distances until the horizon.7 That is a quite esoteric figure to work with, because the radar cross section depends on the angle of observation of the warship, and modern warships employ stealth technology to reduce their radar signature. But if we assume perfect conditions and an aircraft altitude of 10,000 meters, that gives a radar detection range of about 400 kilometers (220 nautical miles). This is theoretically a good coverage, and the aircraft can transmit target data to the ground-based missile launchers. The problem is that contact detection does not equate target identification. In practical terms you cannot shoot if all you have is a bleep on a radar screen. You need the contact to meet certain identification criteria before you decide that it is a valid target, and in most cases that requires closer inspection. This will bring the aircraft into danger from long-range surface-to-air missiles like SM-2 or SM-6. The role of the AWACS must therefore be a retracted one where they direct other assets to inspect contacts of interest. They cannot do it alone.

Another option is to use unmanned aerial drones for surveillance. Russia clearly sees a great potential in this technology, putting many resources into research and development. Small systems like Orlan-10 and Forpost have been operational for some years, and the larger Orion drone is scheduled to enter service later in 2019.8 Drones enjoy long endurance, and they have the advantage that one can take risks with them without jeopardizing the safety of a crew. However, drones are also vulnerable to air-defense weapons. Both Orlan-10 and Forpost drones have been shot down in Ukraine, and it is safe to assume that NATO would be very efficient in picking these airplanes out of the sky. It is therefore unlikely that Russia could use them to solve the problem of target acquisition in an A2/AD system for very long.

Satellite based surveillance

Satellite based surveillance is no panacea to Russia’s challenges of maritime surveillance in an A2/AD scenario. The technology is still immature, and NATO has reliable anti-satellite weapons. There is therefore no reason to believe that Russia can rely on satellite surveillance to provide target data for their coastal missile batteries.

Political limitations to Russia’s sea denial capabilities in the Baltic

Until now I have argued from a technical perspective that it would be difficult for Russia to establish effective sea denial in the Baltic Sea. The range of their missiles is smaller than often assumed, and more importantly they lack surveillance capabilities to conduct effective target acquisition in the maritime domain for a prolonged period of time.

In this section I will complicate matters further. When threat rings on a map are used to illustrate A2/AD bubbles, it is often assumed that these bubbles will be more or less empty. To the extent that there is traffic, it will be friendly units because everyone else must stay out in order to avoid destruction. Therefore, the process of target identification is quite simple, because any unidentified echo on the radar screen must be the enemy. But this is a flawed assumption.

The issue is that war does not happen in a political vacuum. Clausewitz’ theorem that “war is merely the continuation of policy by other means”9 will also apply to the scenario of Russian A2/AD in the Baltic Sea. There will be a reason why we ended up in this situation, and there will be a desire to achieve something.

Typically, the assumed scenario is a Russian invasion of the Baltic States.10 The A2/AD bubble is then intended to play the role of presenting NATO with a fait accompli, because the liberation of the Baltic States would be extremely difficult. Whether one uses this scenario or a less dramatic one, it is clear that Russia would not want a new baseline where they are unable to use the Baltic Sea for trade or fishing. The point of sea denial is to prevent your opponent from using the sea, not to prevent oneself from doing it.

I will briefly point to three political factors that illustrate why Russia cannot keep a clean operating environment in the Baltic Sea for very long. Instead, they would be forced to open up for merchant ships and fishing vessels really quickly, which would make the task of sea denial for NATO’s military forces almost insurmountable.

First, Russia gains tremendously from the internationally regulated system of maritime trade. In 2018, the Russian ports in the Baltic Sea handled more than 246 million tons of cargo, including over 133 million tons of oil products.11 Russia would like this activity to continue, also after a limited military confrontation with NATO. The best-case scenario for Russia would be that everyone accepted “the new normal” as quickly as possible so trade relations could be resumed. It would be essential for Russia that all ports – both their own and the ones in the Baltic States – continue to thrive and contribute to the economy.

Second, Russia’s military goals in the Baltic Region would be limited. In case of an attack on the Baltic States, Russia would face the question of what to do about the other countries in the region. Russia would have an interest in disturbing countries like Finland, Sweden, Poland, and Germany as little as possible, because they may then be more prone to accepting the new geopolitical realities in the region. It would thus be desirable for Russia not to interrupt the merchant traffic to Finland and Sweden, and ferry connections may still operate across the Baltic Sea.

Third, in a well-regulated maritime space, warships also enjoy the freedom of navigation afforded to other ships. If Russia wants to advance the idea that other countries should accept an annexation as a new normal, they would also have to allow these countries to move warships around in a somewhat normal fashion. This can be seen in connection with Russia’s own dependence on the ability to move warships in and out of the Baltic Sea, where they are vulnerable to a naval blockade in the Danish straits. The point is that it would be impossible for Russia to achieve their political goals if they attacked every warship that showed up. At the very minimum they would have to accept that the neutral countries Sweden and Finland could patrol their own waters, and in the longer run it would also be untenable to keep NATO’s warships out.

These three factors all suggest that the operational environment in the Baltic Sea would be complicated for Russia. They would not have neat and empty A2/AD bubbles to deal with, but rather a crowded space of intermingling fishing vessels, merchant ships, and foreign warships. This is the operating environment in which Russia would have to decide which contacts to target with their long-range missiles.

What is A2/AD actually for?

Until now, I have made two basic arguments. From a technical perspective I have made the case that Russia is unable to establish A2/AD bubbles in the fashion that is often depicted in Western analyses. They have some long-ranging missiles, but the surveillance technology is insufficient, so they would be unable to do proper target acquisitioning over a prolonged period of time. From a political perspective I have argued that Russia is unlikely to even try to establish A2/AD in the wake of a military land grab in the Baltic Region. The reason is that such persistent aggressive behavior would make it impossible to for other countries in the region to accept Russia’s claim of a “new normal”.

S-400 Triumph air defense missile system.
Photo: Russian Ministry of Defense

For Russia, this is obviously not news. They are keenly aware of their own technical limitations and political restraints. Nobody in Russia argues that they could get away with military aggression by asserting an A2/AD bubble afterwards. However, that does not mean that A2/AD is an irrelevant topic. Rather, A2/AD plays a central role in Russia’s military strategy, only not in the way that many military analysts in the West assume. In this final section I will discuss what the purpose of A2/AD is from a Russian perspective.

The first thing to notice is that Russia undoubtably enjoys the fact that the West is afraid of their missiles. They rarely miss an opportunity to praise their own technology, and they routinely nurture a narrative of stellar missile performance. This serves the important purpose of giving an impression of ability. As Robert Jervis noted, deterrence is ultimately a question of perception.12 It doesn’t necessarily have much to do with objective reality or the perceptions of others. Russia acknowledges the subjective nature of deterrence, and they have noticed that their long-range missiles provoke a forceful response in the West.

Therefore, Russia maintains the impression that they could potentially establish effective area denial in the Baltic Sea. This is a convenient narrative, because it shifts the power dynamics in the region. Objectively, one might look at a map of the Baltic Sea and notice that NATO controls most of the territory, but by fueling the A2/AD storyline, Russia has effectively shifted the discussion. If the Western powers believe that they only control the Baltic Sea because Russia allows them to do so, then Russia has gained a tremendous advantage.

The other thing to consider is that Russia doesn’t primarily see a scenario where they are the aggressive belligerent. In fact, arguably they don’t see this scenario at all. Instead, they largely assume that the purpose of their armed forces is to deter the West – and most notably the United States – from attacking them. This might seem like a paranoid thought from a Western perspective, but it nevertheless is the premise of the security dilemma that opposite sides perceive the actions of the opponent with concern.13

What this means is that A2/AD can be understood as a tactic that is meant for a rather extreme defense of the homeland. It is not designed as a flexible tool to be applied while one’s country is winning, but as a bulwark against defeat.14 This is a radically different way to understand A2/AD because it changes the time perspective. From being an impenetrable bubble that can be maintained for a long time, A2/AD becomes a part of a layered defense system. In this scenario, Russia does not envision itself as limited by political considerations, because they will be under attack and justified in taking extreme measures. They also will not be limited by the technological shortcomings of their surveillance systems, because they won’t have to do it for very long. Therefore, they can throw all resources into the task at once.


The argument in this paper is that the West typically misunderstands Russia’s ability to establish A2/AD in the Baltic Sea. The notion that maximum missile ranges can be transformed into threat rings on a map is fundamentally flawed. I have used a case study of sea denial in the Eastern Baltic Sea to illustrate the problems with this traditional understanding of A2/AD.

From a technical point of view the idea of impenetrable bubbles overlooks the facts that a) the effective range of missiles is much smaller than the maximum range, and b) the hard part about sea denial is target identification and not to shoot the actual missile. In a war situation, Russia simply does not have the required capabilities to conduct sea denial against NATO for a prolonged period of time.

From a political perspective the traditional idea of A2/AD bubbles is even less credible. In Western debates it is always assumed that the military conflict will be initiated by Russia, and that it involves some kind of territorial occupation. The A2/AD bubble is then imagined as a tool to present NATO with a fait accompli, because any attempt to liberate the lost territories would be a bloodbath. The problem here is that effective sea denial would work contrary to any political goals that Russia could be assumed to have. There is no scenario in which Russia wants to destroy its own maritime economy. Instead, Russia will want its neighboring countries to accept the geopolitical situation as a “new normal”. This will require a quick reestablishment of the internationally regulated system of maritime communications, including the rights of other countries to operate warships in the Baltic. A prolonged period of aggressive A2/AD will almost certainly unite Russia’s neighbors against any notion that the situation is normal.

The proper way to understand the illustrative maps with threat rings is not as A2/AD bubbles, but as outer limits of a layered defense. Nobody expects such a limit to be impenetrable, because the enemy has very few effective weapons at this range. This more sober framework leads to a different interpretation of the meaning of Russia’s long-range missiles. First, Russia’s supposed A2/AD weapons are mostly intended to contribute to a layered defense in case of a Western attack on Russia. They are not omnipotent game changers, and they definitely will not on their own force the West to accept a fait accompli in case of Russian aggression against the Baltic States. And second, Western leaders should not let themselves be guided by a contorted perception of Russian weapon effectiveness. There are definitely reasons to be concerned about Russia and the future stability of the Baltic Region, but A2/AD bubbles are not one of them.

  1. Luis Simon, “Demystifying the A2/AD Buzz,” War on the Rocks, January 4, 2017, https://warontherocks.com/2017/01/demystifying-the-a2ad-buzz/
  2. Ian Williams, “The Russia – NATO A2AD Environment,” Missile Threat, Center for Strategic and International Studies, January 3, 2017, https://missilethreat.csis.org/russia-nato-a2ad-environment/
  3. Sergey Sukhankin, “David vs. Goliath: Kaliningrad Oblast as Russia’s A2/AD ‘Bubble,’” Scandinavian Journal of Military Studies 2, no. 1 (August 21, 2019): 102, https://doi.org/10.31374/sjms.20
  4. Constance Douris, “Lexington Institute,” Lexington Institute (blog), September 19, 2016, https://www.lexingtoninstitute.org/natos-urgent-effort-deter-russian-aggression/
  5. Robert Dalsjö, Christofer Berglund, and Michael Jonsson, “Bursting the Bubble. Russian A2/AD in the Baltic Sea Region: Capabilities, Countermeasures, and Implications” (FOI, March 2019), 29, https://www.foi.se/rapportsammanfattning?reportNo=FOI-R–4651–SE
  6. Anders Puck Nielsen, “Russia Reinforces Baltic Fleet with Submarine ‘Alrosa,’” Romeo Squared (blog), August 31, 2018, https://romeosquared.eu/2018/08/31/submarine-alrosa-reinforces-russian-baltic-fleet/
  7. Jane’s, “Beriev A-50 and A-100 Series,” January 31, 2019, https://janes-ihs-com.ezproxy.fak.dk/Janes/Display/jaem0004-jc4ia. 
  8. TASS, “Russian Defense Firm to Deliver 1st Orion Reconnaissance Drone to Troops by Year-End,” TASS, August 29, 2019, https://tass.com/defense/1075649
  9. Carl von Clausewitz, On War, Indexed Edition, trans. Michael Eliot Howard and Peter Paret, Reprint edition (Princeton, N.J: Princeton University Press, 1989). 
  10. Anders Puck Nielsen, “How Would a War between Russia and the West Play Out?,” Romeo Squared (blog), January 1, 2018, https://romeosquared.eu/2018/01/01/the-military-scenario/; Rowan Allport, “Fire and Ice – A New Maritime Strategy for NATO’s Northern Flank” (London, UK: Human Security Centre, 2018), 45–51, http://www.hscentre.org/wp-content/uploads/2018/11/Fire-and-Ice-A-New-Maritime-Strategy-for-NATOs-Northern-Flank.pdf
  11. Administratsiya Morskikh Portov Baltiyskogo Morya, “Arkhiv Dannykh Po Gruzooborotu,” accessed August 31, 2019, https://www.pasp.ru/arhiv
  12. Robert Jervis, “Deterrence and Perception,” International Security 7, no. 3 (1982): 3–30, https://doi.org/10.2307/2538549
  13. Charles L. Glaser, “The Security Dilemma Revisited,” World Politics 50, no. 1 (1997): 171–201. 
  14. Anders Puck Nielsen, “Militarization in the Baltic and the Arctic Compared: The Arctic Is the Dangerous Place,” Romeo Squared (blog), May 24, 2019, https://romeosquared.eu/2019/05/24/comparing-the-baltic-and-the-arctic-the-arctic-is-the-dangerous-place/




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