American thinkers tend to look at naval strategy as ocean-centric. The seas that matter most are the ones that must be kept open to ensure sea lines of communication: the Mediterranean, the Red Sea, the Persian Gulf, the South China Sea, and the Straits of Malacca. Inland seas receive much less attention. The northeast corner of the Black Sea and the Caspian Sea have relatively little impact on global sea lines of communication, but they could have an important military-strategic role to play. The Caspian and to a lesser extent the Black Sea could serve as impenetrable strategic bastions for Russia and Iran to hide a nearly invulnerable sea-based nuclear strike force.

In 2015 Russia made much of its launch of cruise missiles into Syria from the Caspian Sea. One U.S. official said at the time,

But why did Russia place cruise missiles on an inland sea? If these ships had been located in the Persian Gulf or the Mediterranean, they would have been vulnerable to much more capable Western navies. In the Caspian and Black Seas, Russia is still the dominant naval power.

By placing nuclear-armed cruise missiles in ships and submarines located in the Caspian and Northern Black seas, Russia and Iran could threaten their most important targets without leaving the launchers vulnerable to pre-emption. Russian leaders have already made clear their intention to use the Black Sea for that purpose, and Iran is building a submarine on the Caspian and investing in developing long-range cruise missiles. It probably has a similar purpose in mind.

This inland-sea deployment strategy is an updated version of a Soviet Cold War strategy to overcome U.S. naval dominance: the Bastion strategy. During the Cold War the Soviet navy also had SSBNs just like the U.S. Navy. Unlike the U.S. Navy, whose super-quiet submarines could hide anywhere in the world’s vast oceans, the louder Soviet boats always had to pass through choke points when deploying to the ocean. Russian SSBNs had to run a gauntlet of Western submarine-detection assets, most famously the SOSUS listening system, a global network of underwater microphones. Western anti-submarine warfare (ASW) capabilities also far overmatched Soviet capabilities.

The Soviets turned their geographic liability into a strategic asset, which Western analysts called “strategic bastions” and the Russians call “fortified regions.”¹ Instead of hiding ballistic missile submarines in the open ocean, they hid them in waters the Soviets could control and keep free of Western ASW assets. The important thing about ballistic missile submarines is that they remain both hidden and in range of their targets, and that was a formula that technology expanded during the Cold War era. When in the 1970s the Soviet navy got new R-29 nuclear missiles with a long enough range to reach targets in North America, the Soviets formed bastions in the Barents Sea (which is about the size of Mongolia), the White Sea, the Kara Sea, the Sea of Norway, the Sea of Okhotsk, and the Sea of Japan.²

The Russians have since built their strategic naval strategy around these bastions, but the importance of the bastion idea goes beyond Soviet Cold War strategy. Some observers explain China’s activities in the South China Sea as an attempt to create their own strategic bastion. Unfortunately for the PRC, the South China Sea is also an important shipping artery. In their two large inland seas, Russia and Iran could eventually place strike forces in a bastion that has scant impact on global communications.

The Black Sea: A Russian Bastion to Threaten Europe

The seizure of Crimea and the destruction of the Ukrainian fleet there has made Russia even more dominant in the Black Sea. In the event of a crisis, the powerful Turkish fleet could still prevent the Black Sea from becoming a Russian lake, but a combination of shore-based anti-ship and anti-aircraft missile batteries in Crimea and a renewed Russian Black Sea Fleet, could make portions of the northern and northeastern Black Sea an effective Russian naval bastion. However, instead of stationing ballistic-missile submarines there, Russia could station surface ships carrying intermediate-range nuclear and conventional weapons.

After Russia captured Crimea, it did not stop building its “replacement” naval base in Novorossiysk on the Black Sea. Reportedly the work on the base has been accelerated. Novorossiysk was where the Russian fleet was supposed to relocate to if Ukraine ever kicked it out of Sevastopol. Instead of hosting the core of the Black Sea Fleet, it appears the Novorossiysk base will be dedicated to hosting Russia’s expanding fleet of Black Sea submarines. According to a post on the Russian propaganda outlet Ruptly, during Putin’s visit to the base in September 2014 the Black Sea Fleet commander said that Novorossiysk “is set to accommodate submarines carrying long-range cruise missiles (with a range of over 1,500 kilometers), as the location will allow for better secrecy than maintaining such submarines in the port of Sevastopol.” Russian outlets have stated that six submarines will operate from the Black Sea by the end of 2016, which is down from the “no fewer than” 10 or 12 which they claimed they would build in 2007. In 2000 Russia had only one operational submarine in the Black Sea Fleet.

A recent and much-publicized Russian “first” took place in December, when a Black Sea based improved Kilo-class diesel submarine launched a cruise missile strike into Syria from the Mediterranean in December. A force of Russian submarines carrying conventional and nuclear cruise missiles could provide a sea-based theater deterrent force that could probably not be destroyed in a conventional or nuclear first strike. In addition to submarines, small Russian vessels such as the Buyan-M corvette could be used as mobile sea-based launching platforms for conventional or nuclear cruise missiles—at least one Buyan-M corvette reportedly launched some of the Russian cruise missiles that struck Syria in October 2015. Ships like the Buyan-M are even small enough to travel on Russia’s internal waterways when there is no ice, making them even more mobile. At the time, a Russian admiral put it bluntly: “The range of these missiles allows us to say that ships operating from the Black Sea will be able to engage targets located quite a long distance away, a circumstance which has come as an unpleasant surprise to counties that are members of the NATO bloc.” A Russian Kalibr missile located on a ship or submarine floating east of the Crimean Peninsula could attack targets anywhere in east-central Europe, and this is assuming that the missile only has a 2,000 kilometer range, not the rumored 2,500 kilometer range of the nuclear-tipped Kalibr missile variant.

Furthermore, with a sea-based force Russia could gain a significant edge in intermediate-range nuclear forces in Europe without violating the INF Treaty—not that it has not been violating the treaty anyway. The INF Treaty does not cover sea-based weapons. Hans Kristensen of the Federation of American Scientists has hailed the sea-launched Kalibr missiles as the “savior of the INF treaty,” since they can hit any target that would otherwise be attacked by hypothetical Russian ground-launched cruise missiles. This kind of thinking is the epitome of arms control for its own sake, that ignores real strategic consequences and reverses the logic of means and ends. As to reality, it looks something along the lines of Russian propagandist and naval veteran Konstantin Dushenov’s description back in October 2014:

An Iranian Bastion in the Caspian?

Russia aside, the Caspian is an ideal location for a future Iranian sea-based deterrent. The Caspian Sea is deeper than the Persian Gulf; indeed, the area of the sea closest to Iran is more than 700 meters deep. An Iranian submarine hiding only in the deep Iranian-controlled waters of the southern Caspian could cruise an area roughly the size of Switzerland. Iranian shore-based anti-missile and anti-aircraft batteries could defend this area along with the Iranian navy’s Caspian fleet.

Most importantly, the Caspian is free from any U.S., Israeli, or Saudi anti-submarine assets or naval bases. A moat of land surrounds the sea, making the entry of Israeli or American naval assets from the ocean impossible (without Russian cooperation). A Caspian bastion might also allow Iran to store ballistic and cruise missiles in relatively immobile submersible barges or submarines. If they were regularly re-located and mixed with decoys, they would make it almost impossible for even a determined adversary to conduct a successful counter-force strike with conventional or even nuclear weapons. The southern Caspian is thus a natural “bastion” that could potentially give Iran a large strategic advantage if it ever wants to build a sea-based deterrent.

There is no indication in open sources that Iranian strategists are discussing a “bastion” strategy. But in 1998 Iran test-fired a ballistic missile from a barge in the Caspian Sea. This test is usually referenced as pointing to possible Iranian plans for an EMP attack against the United States from a merchant vessel, but it could also point to an option to base strategic weapons there. The missile fired in 1998 lacked the range to reach anywhere strategically significant other than Baku. If Iran had a missile capable of hitting likely Iranian strategic targets from the southern Caspian, even a low-mobility submersible launcher might suffice to house a credible sea-based strategic strike force.

The possibility of Iran choosing a bastion strategy is not entirely theoretical. Iran would need a submarine and a delivery system for the purpose, and there are indications that it may already be preparing the necessary infrastructure. Jane’s reported that satellite imagery from October 27, 2013, showed the Iranians building a new Fateh (conqueror) class of submarine on their Caspian coast at the Bandar Anzali Naval base, in addition to one already launched on Iran’s southern coast. The last time submarines regularly operated in the Caspian was during World War II, when the Soviet Union tested a new model of submarine there.

In 2012 Iran’s Deputy Defense Minister claimed that Iran was developing a new cruise missile dubbed “Meshkat” (Lantern) with a range of more than 2,000 kilometers and capable of being launched from a submarine. This range is more than enough to reach any Turkish, Saudi, or Israeli target, or any U.S. base in the Persian Gulf from the deep southern area of the Caspian Sea. Of course, claims by Iranian officials about missile ranges must be taken with a grain of salt. This time, though, Iran may not be bluffing. The Meshkat is probably based on the air-launched Soviet KH-55 cruise missile. Ukraine admitted that it sold 12 KH-55 cruise missiles to Iran in 2001. In March 2015 Iran unveiled its new Soumar land-based cruise missile, which has a claimed 2,500 kilometer range (though this range is probably exaggerated).³ However, Iranian cruise missiles launched from the Caspian Sea would need a range of just 1,500 kilometer to cover the Persian Gulf, Turkey, and most targets in Pakistan. Future Iranian submarines or submersible barges based in the Caspian could feel safe enough to surface and then fire cruise missiles in a manner similar to the antiquated American SSM-N-8 Regulus cruise missile, which was deployed in the mid-20^th century.

With a long-range cruise missile, a submarine, and a relatively safe body of water for it to swim in, Iran may soon possess every component of an effective sea-based deterrent except for a warhead small enough to fit on a cruise missile. Of course, Russia would probably object to the Caspian being turned into a launching pad for Iranian missiles, but if Iran wanted to go for a minimum submarine-based deterrent they could develop all the necessary infrastructure separately and combine them discreetly before Russia has time to object. Russia’s leaders have not appeared alarmed at Iranian efforts to build a nuclear infrastructure, selling them nuclear power plants and advanced anti-aircraft missiles. The Russians may be complacent about Iran’s evolving capabilities or overly optimistic about Israel’s and America’s determination to prevent Iran from acquiring nuclear warheads. Hypothetically, if Iran kept the ranges of cruise missiles located in the Caspian at 2,000 kilometers, and kept them in a fortified Iranian bastion in the southern Caspian, the missiles would be unable to reach Moscow but still able to threaten all of Iran’s regional adversaries (and any U.S. bases in the Middle East). While this would not be ideal for Russia, the ability to allow or veto U.S. or Israel access to the Caspian to detect and strike at this hypothetical Iranian force could give Russia a valuable bargaining chip.

Today, even in its depleted condition, the U.S. Navy enjoys an even greater mastery of the world’s oceans than it did during the Cold War. But Iran and Russia can use inland seas to base weapons with important regional strategic implications. The Black Sea is already well on the way to being a Russian Bastion and, as the Russians demonstrated last autumn, the Caspian can already be used as a missile launching pad. The growth of the Iranian Caspian Sea fleet deserves much more attention than it has gotten. While most commentators see Iran’s Caspian activities as tied to ongoing disputes about boundaries and resource allocation, if Iran adopted a bastion strategy the Caspian would quickly become an area of concern for the entire Middle East in the second nuclear age.

Mixed with high-fidelity decoys and surrounded by land-based defense systems, these naval strike forces would be among the hardest of targets, and unlike vessels hiding in the open ocean, it would be relatively easy to communicate with and re-supply launch platforms located in inland seas. If nothing else, these bastions would affect the missile defense plans of NATO, Israel, and the Gulf, and probably also greatly increase the importance of Azerbaijan and Ukraine in the eyes of Naval strategists.

In the future, too, there is no reason that short and long-range ballistic missiles cannot also one day be placed in inland-sea bastions in addition to cruise missiles. There is a precedent: During the Cold War some U.S. planners proposed using the Great Lakes for that purpose.⁴ As Western precision munitions get better and better it becomes ever more important for potential adversaries that their strike forces are mobile and hidden in order to be survivable. Inland seas provide the perfect places to base such forces.