Hudson Institute

A New Black Sea Strategy for a New Black Sea Reality

Senior Fellow, Center on Europe and Eurasia
Senior Fellow (Nonresident)
black sea
Russian diesel-electric Kilo class submarine Rostov-on-Don sails through the Bosphorus Strait on its way to the Black Sea on February 13, 2022. (Photo by Ozan Kose / AFP via Getty Images)

View PDF


With Russia’s large-scale invasion of Ukraine in February 2022, there is a new geopolitical reality in the Black Sea region. Following the capture of the Ukrainian city of Mariupol in May, Russia has effectively turned the Sea of Azov into a Russian lake and is also seeking maximum control of the Black Sea. Turkey has reminded the world of Ankara’s regional importance by closing the Turkish Straits to the belligerent parties’ vessels (in practice the Russian Navy, except for the platforms home-ported in the Black Sea), which it carried out under authority granted by the 1936 Montreux Convention. Despite the overwhelming odds, Ukraine has been able to deliver significant blows to the Russian Navy—most sensationally by sinking the Black Sea Fleet’s flagship Moskva missile cruiser and by striking Russian platforms with unmanned surface combatants in October. 

Black Sea geopolitics is a complex phenomenon. Any comprehensive regional political-military policy must therefore offer a multidomain strategy. This report will focus on the maritime agenda. Future reports will present findings on air warfare and land warfare trends in the broader Black Sea region. 

figure 1

Need for a New Strategy 

The US and its allies need to develop a comprehensive Black Sea strategy that addresses a new geopolitical reality, one shaped most notably by the Russian invasion of Ukraine. This strategy should be based on the following assumptions: 
•    Ankara will continue to block warships from transiting into the Black Sea through the Turkish Straits for the foreseeable future. Although Turkey has invoked Article 19 of the Montreux Convention, which pertains to the belligerents’ navies (vessels that are not home-ported in the Black Sea), the Turkish Foreign Office’s diplomatic rhetoric implied that Ankara would also prohibit outsider naval activity.1  There is no reason to assume this restriction will be lifted anytime soon, as the closure is directly linked to the ongoing war. These restrictions have implications for NATO and Russia: they will reduce NATO’s maritime presence in the Black Sea and will reduce Moscow’s ability to project maritime power in the Eastern Mediterranean. The Russian General Staff cannot send non–Black Sea naval platforms into the hot zone until the war comes to an end. Russia’s Black Sea Fleet is on its own now. As policymakers develop a Black Sea strategy, they will need to consider these important facts. 
•    The combat-tested maritime defense capabilities rapidly developed by Ukraine offer an opportunity to improve the security of the Black Sea and beyond. Ukraine’s domestically produced anti-ship cruise missile Neptune, combined with creatively used and adapted disruptive weapons systems like the Bayraktar TB2 drones, Harpoon anti-ship missiles, and the Naval Strike Missile, has proven to be effective at coastal defense. At the time of writing, Ukraine has destroyed eight Russian naval ships and damaged another four2—even though Ukraine effectively does not have a navy. Lessons learned by Ukraine could be applied to a new generation of coastal defense and a new concept of operations (CONOPS)—centered on robotic warfare capabilities, information superiority, and anti-ship missile edge—which could be relevant in places like Azerbaijan on the Caspian Sea and even Taiwan.
•    Romania has the geostrategic edge to become a central A2/AD (anti-access/area denial) hub for NATO. In response to the heightened Russian threat to European security, the alliance has augmented the allied military posture in its eastern frontiers. By establishing new multinational battle groups in the alliance’s east (Bulgaria, Slovakia, Romania, and Hungary), NATO has geopolitically extended its Enhanced Forward Presence from the Baltic Sea in the north to the Black Sea in the south.3  A logical next move would be augmenting Romania’s A2/AD capacity by deploying a complex deterrent of anti-ship missiles, layered air defenses, heavy MLRS (Multiple Launch Rocket System), and tactical ballistic missile systems (i.e., HIMARS/ATACMS) as well as potent aerial and naval robotic warfare systems. 
•    The war in Ukraine will continue, in some form, for the foreseeable future. Neither Russia nor Ukraine has shown a willingness to negotiate. Due to the successful counterattacks in Kharkiv and Kherson in the autumn of 2022, Ukraine sees itself on the front foot for the first time in the war. Meanwhile, President Vladimir Putin’s illegal annexation of Ukraine's Luhansk, Donetsk, Kherson, and Zaporizhzhia regions, and the recently announced mobilization to reinforce the Russian military, demonstrate that Moscow has no interest in peace talks. Furthermore, massive Russian mobilization and conscription efforts have inevitably altered force-to-terrain and force-on-force ratios. While these force generation measures will not win the war for Putin, they can potentially sustain a highly attritional stalemate. Policymakers need to understand that the war in Ukraine will likely last for a long time, even years, and they need to start planning accordingly. 
•    The Russian Black Sea Fleet and military presence in Crimea are problems not only for NATO’s east but also for its south. Russia’s 2015 expedition in Syria was logistically and militarily enabled by the Black Sea Fleet, home-ported in Sevastopol, Crimea. The illegal annexation of the peninsula has secured a dangerous gateway for cementing the Russian presence in NATO’s south. Furthermore, the Black Sea Fleet expanded the Tartus base in Syria. The facility, a remnant of the Cold War, has turned into a Mediterranean stepping stone for the Kremlin’s great power ambitions. Then NATO Supreme Allied Commander Europe General Philip Breedlove considered the Russian contingent in Syria to be an “A2/AD bubble.”4 More importantly, the Russian Black Sea Fleet’s submarine activity via the Turkish Straits, including the dispatch of the improved Kilo-class submarines to execute combat operations in the Levant, marked an open violation of the Montreux regime. This menacing Russian “arc of steel” even extended to Libya to support the Wagner private military company’s subversive operations.5 Turkey interrupted Russia’s “Syrian Express”6 by invoking the Montreux Convention’s Article 19. Nevertheless, when the dust settles in the Black Sea region, Moscow will want to return to the status quo ante bellum. Overall, helping Ukraine recapture its sovereign territory of Crimea is a strategic priority for keeping NATO’s east safe, while tackling Russian aggression in the Black Sea is a security matter for the alliance’s south.  
•    Turkey will continue to play a special role in the Black Sea region. In a nutshell, Turkey is the most status quo–driven littoral state in the Black Sea. In the eyes of the Turkish elite, the status quo in Turkey’s northern waters is manifested by the Montreux Convention; for Ankara, anything else in the Black Sea calculus is transactional. While Turkey’s prioritization of the status quo has at times led to convergences between Turkey and Russia, Ankara’s calculus also extends to halting the Kremlin’s aggressive stance in the region. Back in 2015, when Turkey’s downing of a Russian Su-24 frontline bomber led to a Turkey-Russia rupture, it was Turkey that called for more NATO activity in the region, pointing out the risk of the Black Sea turning into a “Russian lake.”7 Thus, Russia’s illegal annexation of Crimea and the Russian military’s attempts to seize Odesa also fall under unacceptable revisionism in the Turkish geopolitical paradigm. This is why, when the war erupted, the Turkish government’s initial playbook involved invoking the Montreux Convention, intensifying military assistance to Ukraine, and in the meantime keeping the intelligence and diplomatic outreach to Moscow strong. For geographical, economic, political, and historical reasons, Turkey sees itself as having a special role in the Black Sea region. Russia’s invasion of Ukraine has highlighted this fact. Policymakers should embrace Turkey’s self-understanding and harness its influence and role in the Black Sea region to bring about security and stability. Finally, while Turkey’s Montreux sensibilities are there to stay, Ankara’s regional ownership paradigm in the Black Sea has come to its limits. Following the Russian invasions of Georgia and Ukraine, it is almost impossible for any Turkish government to pioneer joint regional initiatives that incorporate NATO allies, partners, and Russia. This is why Turkey’s Western allies should focus on a new Black Sea cooperation model with Ankara—including intra-NATO naval cooperation models between the three littoral allies—instead of hopelessly asking for concessions relative to the Montreux regime.
•    Russian military capabilities and readiness in the Black Sea will remain at a reduced level. This situation will have an impact on Russia’s maritime presence in the Caspian Sea, Baltic Sea, and Eastern Mediterranean. Under the restrictions of the 1936 Montreux Convention, Russia cannot reinforce its naval presence in the Black Sea from anywhere but the Caspian Sea8—and here Russian options remain limited. The closure of the straits to warships will also have a medium- and long-term impact on Russian maritime operations in the Eastern Mediterranean supporting Syria. 

Five Reasons Why the Black Sea Is Important

The Black Sea sits at an important crossroads between Europe, the Middle East, and the greater Caspian region. There are five Black Sea littoral countries: Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. While Moldova does not have a Black Sea coastline, it is geopolitically part of the region. The Moldovan port of Giurgiulesti also connects the country to the Black Sea via the Danube River. 

Throughout the history of the region, the Black Sea has proven to be geopolitically and economically important. Even for a country located thousands of miles away, like the United States, the Black Sea is critical to transatlantic interests and America’s geopolitical roadmap. There are five main reasons why the Black Sea is strategically important to the US:

First, the Black Sea region is home to reliable allies and partners. Three Black Sea states (Bulgaria, Romania, and Turkey) are in NATO and fall under the alliance’s collective defense guarantees; these stem from the Washington Treaty’s Article V, which contains a clear casus foederis clause. Another two countries (Georgia and Ukraine) aspire to join the alliance. It is also worth noting that Black Sea countries have demonstrated a greater political will to deploy troops in support of NATO operations than countries in other regions. For example, in the final years of the NATO-led mission in Afghanistan, one-third of all the European forces serving were collectively contributed by Bulgaria, Georgia, Romania, Turkey, and Ukraine.

Second, the Black Sea region is home to unfinished business for Euro-Atlantic integration and NATO. Euro-Atlantic integration has been successful across much of Europe, but the region around the Black Sea remains an area for NATO and European Union enlargement. Moldova, Georgia, and Ukraine each have varying degrees of engagement with the EU and NATO. Moldova and Ukraine are officially candidate countries for the EU, while due to concerns about democratic backsliding, Georgia retains the official status of “applicant.” All three are also in the EU’s Eastern Partnership program and have association agreements with the EU. Turkey has also been an EU candidate country since 1999, although no meaningful progress has been made in recent years. Georgia has sought to join NATO since 2008, but French and German political weakness has blocked any meaningful progress. In October 2022, Ukraine officially applied for NATO membership, but its prospects of joining the alliance remain low while it is engaged in a war with Russia. Moldova has not officially declared its intent to join NATO, but Dorin Recean, the country’s national security advisor, recently stated that “Moldova can no longer rely exclusively on foreign policy instruments, one of which is its neutral status, to ensure state stability.”9 This has been the strongest statement in recent years by a senior government official that Moldova might consider a NATO path. 

Third, the Black Sea region is an important regional transit and shipping hub. Some of the world’s most important shipping lanes, oil and gas pipelines, fiber-optic cables, and trade routes crisscross the Black Sea or connect to it. Two major fiber-optic cables cross the Black Sea: the Caucasus Cable System and the Black Sea Fiber-Optic Cable System. The region is also rich in natural resources. While exact totals are not publicly available, it is estimated that the Black Sea holds trillions of cubic meters of natural gas and 10 billion barrels of crude oil reserves.10 As hydrogen becomes an increasingly important part of the energy mix, the Black Sea will also play a role. The region has been described as the “next hydrogen hub.”11 A network of important oil and gas pipelines connects the Caspian Sea region to the Black Sea. 

Fourth, Russia uses the Black Sea as a platform for operations further afield, and this has consequences that affect the Middle East. For example, Russia has used its Black Sea presence in occupied Crimea to launch and support naval operations in support of Syrian President Bashar al-Assad. In the early days of Moscow’s intervention in Syria, the Moskva—a Russian Navy guided missile cruiser and flagship of the Black Sea Fleet before it was sunk by Ukrainian forces in April 2022—played a vital role in providing air defense for Russian forces.12 Hundreds of thousands of tons of grain and wheat have been shipped from Crimea to Syria to help the Assad regime address food shortages.13 Hundreds of trips have been made between Crimea’s port city of Sevastopol and the Russian naval base in Tartus to transport military hardware and resupplies.14

Finally, in an era of great power competition, China and Iran also play a role in the Black Sea that policymakers need to be aware of. China sees the Black Sea as part of the European terminus of its Belt and Road Initiative and has been investing in the region. Nonetheless, it has not been able to establish the same economic toehold in the Black Sea that it has in regions like sub-Saharan Africa and Latin America. Furthermore, European countries are increasingly aware of China’s predatory investment practices. To the south, Iran wants to establish a Persian Gulf–Black Sea connectivity route via the Caucasus. Tehran sees this as another possible way to engage with the outside world when economic sanctions limit options. Last year, Iranian Foreign Minister Hossein Amirabdollahian hosted Lazar Comanescu, the secretary general of the Organization of Black Sea Economic Cooperation, in Tehran to discuss possible areas of cooperation.15 Iran’s desire to be more involved in the region is something that policymakers should be watching closely. 

Iran has become the primary supplier of drone warfare systems to the Russian military amidst the ongoing war in Ukraine. As of January 2023, Iranian loitering munitions and (probably) ballistic missiles have become Black Sea and Eastern European threats for NATO allies and partners. In return, Tehran is set to receive advanced Russian weapon systems, including the Su-35 air superiority aircraft. Overall, the Russia-Iran military axis has become more dangerous than ever with the new geopolitical situation sparked by the war in Ukraine. 

Turkey’s Role as “Chimera” in the Black Sea

Turkey’s Black Sea policy is complicated and best described as a chimera. Like the mythological creature that was part lion, part goat, and part snake, the Turkish Black Sea policy combines disparate elements, all of which need to be considered. Put another way, the contemporary Turkish Black Sea paradigm is multifactorial: it is the product of different policy vectors, following different political-military directions, and eventually forming a complex strategic outlook. It has four main pillars: 
1.    Primacy of the Montreux Convention regime in Black Sea political-military affairs. While most writings have confused this stance with an effort to maintain balance with NATO and Russia, the primacy accorded to the Montreux Convention is actually a function of Turkey’s NATO membership, which urges the nation to prevent any potential trouble in its northern waters. Given its collective defense responsibilities within the alliance, and specifically those outlined under Article V of the Washington Treaty, the Turkish government cannot keep a neutral stance if another NATO member is attacked.
2.    Importance of maintaining the “diplomatic edge” in the region. To date, Turkey has been skillfully managing competition and cooperation with Russia, essentially through compartmentalization and transactionalism—two concepts that sum up a long history of complex bilateral relations. Turkey has taken a leading role in founding multilateral mechanisms in the region in order to prevent the Black Sea from turning into a theater of military conflict between NATO and Russia. In the event of such a clash, Turkey as a NATO member could not stay neutral. 
3.    Turkey’s NATO nation status. Turkey joined NATO in 1952. During the Cold War, Turkey was one of only two countries that actually bordered the Soviet Union (the other one being Norway). Turkey is home to a major air base at İncirlik, which is primarily used by the United States, and the NATO Land Command. The X-band radar at the Kürecik Radar Station in south-central Turkey is a crucial component of Europe’s missile defense system; geometry and geography make Turkey the best location for this radar. Turkey is a staunch supporter of NATO’s open-door policy (though this fact does not dominate headlines in Western news outlets), and it has supported NATO membership for Ukraine and Georgia. More importantly, Turkey, with its robust naval posture and burgeoning robotic warfare edge, remains the most potent Black Sea littoral nation within the NATO alliance. In other words, a military net assessment would suggest that Turkey more or less is NATO in the Black Sea. 
4.    Turkey’s growing defense ties with Ukraine. Ukraine offers Turkey a Western but non-NATO defense collaboration—similar to the partnership with the Israeli military in the 1990s—that provides for more generous technology transfer and coproduction than the Euro-Atlantic countries offer. While many experts anticipated that the Turkey-Ukraine defense ties would weaken following Russia’s invasion of Ukraine, Ankara and Kyiv have in fact intensified their collaborative efforts in codeveloping critical military technologies. Turkey’s historical kinship ties to the Crimean Tatar population, oppressed by the Russian invasion after 2014, adds a special edge to the growing Turkey-Ukraine strategic bilateral ties. 

The Core Paradigm: Montreux Convention for Beginners

The 1936 Montreux Convention, which regulates the transit of warships through the Turkish Straits of the Bosporus and Dardanelles, forms Turkey’s leading paradigm in the Black Sea. 

The convention oversees certain restrictions on the transit of warships for non-littoral countries. No more than nine warships belonging to Black Sea outsiders are allowed to transit the Black Sea at a time, and the aggregate total tonnage for the transiting flotilla cannot exceed 15,000 tons. For warships of a single non-littoral state, the maximum aggregate tonnage permitted at one time is 30,000 tons. The total non-littoral naval presence cannot exceed 45,000 tons. The convention also prohibits non-littoral navies from remaining in the Black Sea for more than 21 consecutive days and requires visiting navies to notify Ankara at least 15 days before they sail through the Turkish Straits.16

The Montreux Convention also includes categorical limitations. Aircraft carriers are not allowed to transit the Turkish Straits to the Black Sea. Submarines of the Black Sea littoral states are permitted to transit the Turkish Straits, but they are subject to strict regulations. They cannot submerge in the Turkish Straits, for example, and they may pass through the Turkish Straits only “for the purpose of rejoining their base in the Black Sea for the first time after their construction or purchase, or for the purpose of repair in dockyards outside the Black Sea.”17 This is why Russian submarine activity in Syria is a clear violation of the convention. 

The delicate balance established by the Montreux Convention played a key role in keeping the Black Sea region stable during the Cold War, when relations between NATO and Warsaw Pact countries were tense. This mainstream line of thought in Turkey argues that Russia has no wish to change the Montreux regime because Moscow sees it as a barrier keeping Western capabilities from pouring into its southern seas.18 Ankara’s invocation of the Montreux Convention in 2008, during the Russian invasion of Georgia, is a good example of the Turkish perspective. At the time, Ankara turned down the passage of USNS Comfort and USNS Mercy, hospital vessels carrying humanitarian aid to Georgia. While the ships were not surface combatants, their weight—69,360 tons each—violated the Montreux size limits.19 This refusal does not mean that the Turkish government sided with Moscow against Tbilisi. Weeks later, Turkey permitted the USS McFaul, USS Mount Whitney, and USCGC Dallas to pass through the Turkish Straits en route to Georgia because their passage complied with the terms outlined in Montreux. 

Turkey’s Dual Track: Pursuing the NATO Agenda While Keeping the Balance with Russia

Since its accession to the alliance in 1952, Turkey has been an important NATO nation, with robust warfighting capabilities and unique geopolitical characteristics. Turkey is NATO’s window toward the former Soviet space. It is the only NATO country with a Caucasus, Middle Eastern, Black Sea, Balkan, and Mediterranean frontier, all in one. Without Turkey, the Aegean would have marked NATO’s eastern end; and the Turkish Straits, connecting the Mediterranean to the Black Sea, would be totally alien to the alliance. During the Cold War, a nonaligned Turkey would have meant facing at least 22 more Soviet Red Army divisions in Eastern Europe. 

More importantly for NATO, only a few other allies match Turkey’s military capacity, which is a true realpolitik factor to incorporate in any net assessment (and one often neglected nowadays). At present, only the American and Turkish militaries outnumber the Russian Western Military District’s doctrinal order of battle. In more than half of NATO member countries, the overall armed forces are outmanned by the 45,000-strong Russian VDV, the airborne service.20 While these facts were merely statistics before the Ukraine war, they are bitter realities with dire defense policy outcomes at present. 

Turkey has traditionally pursued two separate geopolitical paths in the Black Sea. One of them, naturally, stems from the nation’s NATO identity. When Bulgaria and Romania strived for NATO membership, for example, Turkey firmly supported their accession.

The other track, however, pertains to Ankara’s geopolitical view of the strategically critical Black Sea agenda. By the end of the Cold War, Ankara’s utmost priority was to forge regional cooperation in the Black Sea. The approach was equally appealing to all littoral states, including Russia. In the eyes of the Turkish elite, regional consultation mechanisms could address regional disputes, thereby avoiding complicated crises that could attract intervention by outsiders. Moscow agreed to follow Turkey’s way, as it saw the regionalization of Black Sea affairs as a means to curb transatlantic influence in its south. The Turkish policy was manifested by the Black Sea Economic Cooperation (BSEC), which was established in 1992 to foster regional dialogue and economic engagement. 

Augmented strategic dialogue between Russia and Turkey has led to the emergence of several cooperation frameworks. The most notable policy outcome driven by Turkish initiative is the BLACKSEAFOR (Black Sea Naval Cooperation Task Group), established in 2001 with the participation of Turkey, Russia, Georgia, Ukraine, Romania, and Bulgaria in order to boost regional security cooperation concerning naval and coast guard agendas. 

Ankara’s decision to launch Operation Black Sea Harmony in March 2004 can be viewed mainly as part of its effort to maintain a delicate strategic balance and regional cooperation in the Black Sea. The operation, which was later joined by Russia and other Black Sea littoral states, was designed to counter terrorist threats, mimicking NATO’s Operation Active Endeavor in the Mediterranean following the 9/11 terror attacks. While serving counterterrorism purposes, the Black Sea Harmony was also meant to foster Russian-Turkish security dialogue and to keep the Black Sea stable amidst turbulent conditions. Both the BLACKSEAFOR and Operation Black Sea Harmony are defunct today due to the breakdown in relations with Russia and other Black Sea nations. 

The Limits of Transactionalism and Compartmentalization

Although Turkey-Russia ties can seem complicated, a careful examination reveals a meaningful pattern. The relations between the two nations are shaped by carefully compartmentalizing various activities—that is, by keeping cooperative activities separate from those related to areas of conflict. For example, Turkey and Russia were on conflicting sides in Libya, but they managed to carry on with the S-400 strategic SAM system acquisition. Back in 2019, at a time when the Turkish TB-2 combat drones were pounding the Kremlin-backed and Russian-manufactured Pantsir air defense systems in the Libyan battleground, Russian cargo aircraft were delivering the S-400s to the Turkish Air Force. 

Likewise, while the Turks and the Russians were on competing sides in the former Soviet space, they managed to maintain a bare minimum of cooperation in Syria. While the incumbent Turkish government repeatedly condemned Russia’s actions in Libya and its illegal annexation of Crimea,21the very same administration did not refrain from procuring the S-400 that triggered sanctions under the US CAATSA (Countering America’s Adversaries Through Sanctions Act). 

Nevertheless, Turkey’s relations with Russia and Ukraine (and the transatlantic alliance more broadly) have often been misunderstood by the Western strategic community, which sees Ankara’s calculus as a “balancing act.” However, Turkey-Russia and Turkey-Ukraine ties structurally differ in their geopolitical DNA. 

This compartmentalization by both Ankara and the Kremlin is pragmatic in nature and inherently favors selective and limited cooperation. The limited cooperation paradigm is married to “contained confrontation” when the strategic interests of Turkey and Russia remain at odds; in this way it highlights the transactional character of the bilateral ties. The contained confrontation pattern has from time to time been breached by worrisome exceptions, such as the Turkish combat air patrols’ downing of a Russian Su-24 frontline bomber in 2015, or the killing of 36 Turkish troops in the Idlib, Syria, countryside in 2020. Yet ties between Ankara and Moscow withstood both incidents. 

Nevertheless, a careful assessment of the Russian military leadership’s rhetoric before the full-scale invasion of Ukraine shows that the “Kalibrization” of the Russian Navy—the equipping of the Russian Navy with Kalibr cruise missiles that provide a long-range conventional strike capability—was a turning point in Moscow’s strategic calculus. “Kalibrization” allowed the Caspian Flotilla to launch long-range attacks from the Caucasus frontier and enabled the Black Sea submarine fleet’s missile launches from the Mediterranean. Following these sensational Kalibr salvos in Syria, Chief of Staff Valery Gerasimov claimed that the Russian naval edge was then superior to that of Turkey in the Black Sea. Gerasimov even claimed that Russia could easily strike the Turkish straits.22 Before Russia’s full-scale invasion of Ukraine, the Russian Black Sea Fleet fielded 21 pieces of principal surface combatants, seven pieces of submarines (six improved Kilo-class with Kalibr launch capability), and almost 30,000 personnel.23 Militarily, Russia’s improved Kilo-class submarine modernization of the Black Sea Fleet and the Kalibr missile program both pose direct threats to Turkey. More importantly, by sailing the improved Kilo-class submarines back and forth for combat operations in Syria, the Russian Black Sea Fleet has already violated the Montreux regime itself. Turkey has likely felt it had to accommodate the Russian violations, given the perceived lack of support from its NATO allies following the downing of the Russian Su-24 at the outset of Moscow’s Syria expedition. 

After Russia’s illegal annexation of Crimea in 2014 and the commencement of Russian combat operations in Syria in 2015, Turkey observed that the invasion of Crimea enabled the Russian expeditionary campaign in the Levant. The “arc of steel” then extended to Libya. Of greater concern is the Russians’ enhanced military posture in Crimea after the annexation, which includes dual-capable assets like the Tu-22M3 tactical bomber certified for nuclear roles. 

These Russian moves marked a dead-end for Turkey’s Black Sea regional dialogue plans. The ongoing invasion in Ukraine has been the final manifestation of a bitter truth: Russia’s siloviki elite did not completely agree with Turkey. They only acted as if they did to avoid further NATO presence in their south. All in all, Turkey is a status quo keeper in the Black Sea region; and in the eyes of any Turkish government, the status quo is centered on the Montreux Convention. Indeed, Turkey’s “regional ownership” strategy in the Black Sea has, at times, brought Ankara and Moscow closer. Yet such pragmatic convergences only happened in order to deny outsider influence that could lead to spiraling tensions.24 At the same time, however, Turkey did not refrain from selling critical weaponry to Kyiv to defend against the Russian invasion. Turkish TB-2 drones even took part in the sinking of the Russian Black Sea Fleet’s flagship, the Moskva missile cruiser.25

The Caspian Sea and Sea of Azov Connection 

figure 2

The Caspian Sea is an important, if often-overlooked, region for the United States. It is at the heart of the Eurasian continent, is a crucial geographical and cultural crossroads linking Europe and Asia, and for centuries has proven strategically important to many countries for military and economic reasons. It remains so today. 

The Sea of Azov is a small body of water once shared between Russia and Ukraine and connected to the Black Sea by the Kerch Strait. However, since Russia’s large-scale invasion of Ukraine in February 2022 and the fall of Mariupol in May of that year, the Sea of Azov has effectively become a Russian lake. 

In the broader discussion about security in the Black Sea region, the Caspian Sea and the Sea of Azov are often an afterthought. However, there are three reasons why the security of all three seas is intertwined, and why the US and NATO cannot operate in one without considering the implications and security situation in the others.
1.    One of the two canals connecting the Caspian Sea to the outside world is the Volga–Don Canal,  which links the Caspian Sea with the Sea of Azov. During the spring and summer months, when the canal is not frozen, Russia uses the Volga–Don Canal to move warships between the Caspian Sea and the Black Sea via the Sea of Azov. Ships from Russia’s Caspian Flotilla have played a direct role in supporting Russia’s full-scale invasion of Ukraine since February 2022. 
2.    Russian warships operating from the Caspian Sea have launched cruise missiles against Ukraine. In the past, Russian cruise missiles from the Caspian were also used against targets in Syria. 
3.    Iran and Moscow share many goals in the Caspian region. Russia-Iran cooperation in the Caspian threatens the broader region, including NATO and its partners. The Russian and Iranian navies conduct joint military exercises in the Caspian. It has long been suspected that Iran has transported oil to Russia using the Caspian as a way to skirt economic sanctions. Most importantly, the Iranian drones used by Russia in Ukraine were transported by ship to occupied Crimea via the Caspian and Volga–Don Canal or by an air corridor over the Caspian. 
The ability to move warships from the Caspian region to the Black Sea (and vice versa) allows Russia to project power in an important area of the world while giving Russian policymakers flexibility and options during times of conflict in the broader region. Russia sees the Caspian and Black Seas as being one geopolitical space—and so should NATO military planners and policymakers. 

The Way Forward 

Russia’s invasion of Ukraine means that the old way of thinking about the Black Sea no longer applies. Russia’s war is also a reminder of the geopolitical importance of Turkey as a member of NATO and a Black Sea littoral nation. The US should be a leader within NATO and develop a new strategy for Black Sea security. The US and its NATO allies can do this by taking the following actions:
•    Preparing to establish a Black Sea Maritime Patrol mission as soon as Turkey lifts its restrictions on foreign warships transiting the Turkish Straits. NATO should establish a Black Sea Maritime Patrol mission modeled on the successful Baltic Air Policing mission in order to maintain a robust NATO presence in the Black Sea that is in line with the 1936 Montreux Convention. This would require non–Black Sea NATO countries to commit in advance to a regular and rotational maritime presence in the Black Sea.
•    Supplying more ships to allies and partners in the region. The right to self-defense does not stop at the shoreline. As described above, the Montreux Convention places restrictions on the size and number of non–Black Sea warships that can enter the Black Sea at one time.27 There are also restrictions on the length of time each warship from a non–Black Sea country can remain in the Black Sea. The most direct way around these obstacles is to help allied and friendly countries in the region increase the size and capabilities of their navies. In coordination with Turkey, the US should develop individual maritime security action plans for Bulgaria, Romania, Ukraine, and Georgia to improve the navies of each. Finally, among NATO-member Black Sea allies, Turkey has a fast-growing unmanned surface combatants program. Extending Turkey’s rising robotic naval warfare edge to other allies and partners in the Black Sea would be a smart move and could be done by relying on related allied frameworks, such as NATO’s DIANA (Defense Innovation Accelerator for the North Atlantic) project. 
•    Boosting allied A2/AD capabilities. In addition to building and augmenting allied navies, NATO should build robust coastal defense networks, improve radar systems, and enhance surveillance capabilities. The case of the Moskva missile cruiser revealed the vulnerabilities of the Russian Black Sea Fleet. More significantly, building coastal defense networks is cheaper and more sustainable than investing in traditional navies. 
•    Leveraging the US Coast Guard. When Turkey lifts its restrictions on foreign warships transiting the Turkish Straits, the US should develop a plan for the US Coast Guard to become more active in the Black Sea.28 There is a precedent worth building on: in 2021, the USCGC Hamilton completed a visit around the Black Sea, marking the first time the US Coast Guard had operated in the Black Sea since 2008, when Russia invaded Georgia. 
•    Opening a NATO-certified center of excellence on Black Sea security, led jointly by Turkey and Georgia but located on Georgian territory. There is no precedent for a NATO-certified center of excellence in a non-NATO country, but establishing one could improve NATO-Georgia relations and show how important the Black Sea region has become for Europe’s overall security. The center of excellence would provide a forum for meaningful dialogue and training on how to address the challenges associated with Black Sea security. Having joint Turkey-Georgia involvement would also illustrate how NATO and non-NATO Black Sea countries have to work together in the region. 
•    Calling for the creation of a Four Seas Initiative to include the Adriatic, Baltic, Black, and Caspian Seas. This initiative could be based on the existing Three Seas Initiative—a block of regional countries in Central and Eastern Europe connected politically, economically, and geographically to the Adriatic, Baltic, and Black Seas.29 Including the Caspian and associated countries in the region would reflect the interdependence of the region in matters of economic development and transport. Currently, the Three Seas Initiative includes only EU member states. This serves as an artificial constraint to regional cooperation since so many countries in the region are not EU members. Creating a Four Seas Initiative will force the region to look beyond the EU.
•    Getting more diplomatically engaged in the region using the GUAM format. The Organization for Democracy and Economic Development–GUAM is a regional bloc that encourages cooperation between Georgia, Ukraine, Azerbaijan, and Moldova. All four countries are important for advancing US national interests in the region. Russia is almost solely consumed by events in Ukraine and the impact of economic sanctions. The US should take advantage of Russia’s unbalanced geopolitical equilibrium and start engaging more with groupings like GUAM. Congress should host a special interparliamentary gathering with legislators from GUAM parliaments to build relations and explore areas of cooperation. The last US-GUAM meeting at the foreign ministers’ level took place in 2017. Secretary of State Antony Blinken should immediately ask to host a US-GUAM summit to boost cooperation between the US and the GUAM countries.
•    Factoring in the strategic connection between the Sea of Azov, the Volga–Don Canal,26 and the Caspian Sea when developing any Black Sea strategy. Russia places a high importance on the Volga–Don Canal because it connects the Sea of Azov (and the Black Sea) to the Caspian Sea, thereby allowing it to advance its war aims in Ukraine. Russia routinely launches cruise missiles from ships in the Caspian against targets in Ukraine. Iran increasingly supports Russia’s war efforts by transporting drones across the Caspian for use in Ukraine. Therefore, in practical terms, NATO planners need to see the most extreme point of NATO’s Black Sea frontier as being the southern shoreline of the Caspian Sea. 
•    Helping friendly Caspian countries improve their maritime security. The Caspian region is of vital importance to the Black Sea—especially in terms of energy and commercial transit. The US should work in coordination with Turkey to improve the security and military capabilities of partners in the region—especially Azerbaijan and Kazakhstan. The US government’s decision to provide military assistance to another country should be based on American security interests and not pressure from certain groups lobbying Congress. 
•    Working closely with Turkey. Any proposals to increase US involvement in the Black Sea should include involvement and consultation with Turkey. Turkey is a NATO member with sovereign control of the straits, and Washington should assure Ankara that nothing the US or NATO does in the Black Sea is meant to undermine this control. The goal is to increase NATO’s presence in the Black Sea to deter and, if required, defeat Russian aggression. Turkey’s Montreux-driven policy is clearly there to stay. Nevertheless, Ankara’s regional cooperation frameworks, which have traditionally encouraged the participation of Russia and other Black Sea countries, are no longer in place. No Black Sea nation would want to sit down with the siloviki-ruled Moscow following the invasion of Ukraine. Thus, the US should work closely with Turkey to establish new cooperation models in the Black Sea and foster strategic interactions between NATO allies and partners of the region. 
•    Ensuring NATO’s door remains open to Georgia, Moldova, and Ukraine. No non-NATO country, including Russia, should have a veto on the future potential membership of Georgia, Moldova, or Ukraine. These three Black Sea countries know what suffering from Russian aggression is like. Ukraine and Georgia aspire to join the alliance someday. Moldova may seek membership in the future. Without close cooperation and relations with all three, NATO cannot have an effective Black Sea strategy. 
•    Fostering Turkish-Ukrainian defense ties. Ankara’s Black Sea policy is not neutral, let alone aligned with Russia. Turkey has a deep-rooted defense partnership with Ukraine. Ankara and Kyiv enjoy a growing military cooperation portfolio, ranging from coproducing Turkey’s indigenous MILGEM-class corvettes in Ukrainian docks to flying Turkish drone-maker Baykar’s first turbofan-powered unmanned aircraft, Kizilelma, with Ukrainian aerial engines. Endorsing and encouraging the Turkey-Ukraine defense partnership should be a geopolitical priority for the US and other NATO members. In the long term (and especially if Ukraine is to become a NATO ally), the bilateral Turkey-Ukraine defense ties could become a military alliance, forming a natural geopolitical counterbalance against Russian aggression.

View PDF