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The Black Sea as Mare Clausum

Turkey’s special role in the regional security architecture

SWP Comment 2023/C 33, 21.06.2023, 7 Seiten



The Black Sea is a region of tension. It is the arena of the Russia-NATO confrontation while at the same time serving as a projection area for Russian and Turkish visions of regional order. Turkey’s special role in the region stems primarily from the imple­men­tation of the Montreux Convention, which for much of the last century has meant a reduction in unilateral spheres of influence and dominance. The non-ripar­ian states are supposed to be excluded. For Turkey, the Montreux Convention is a lever of power. Russia’s invasion of Ukraine in February 2022 has enabled it to use this lever even more in the service of its own interests. NATO’s room for manoeuvre, on the other hand, has been reduced in the current situation. Turkey is an essential element in the Alliance’s collective defence. However, since the outbreak of the Rus­sian war against Ukraine, NATO is no longer present in the Black Sea. This means that an important pillar of deterrence and defence is missing. In this respect, there is a dualism regarding the conceptions of order in the Black Sea region at two different levels: the regional and the global.

Since the start of Russia’s war in Ukraine on 24 February 2022, many observers have been reminded of the geostrategic interplay of spheres of influence and interest in the Black Sea region, the roots of which go back a long way. For centuries, Russia has pur­sued its desire in ice-free and, to the extent possible, year-round access to the vital sea lanes around Europe in the Black Sea, which underpins its claim as a maritime power. As early as 1770, Catherine II used a formation of the Baltic Fleet to sink large parts of the Ottoman Fleet in a surprise attack in the Aegean Sea, thus expanding Russia’s sphere of influence in the Black Sea. Thanks to this increase in power, Catherine secured large areas of Belarus, Lithuania and eastern Poland in 1772 in negotiations concerning a territorial divi­sion in Eastern Europe.

The historical battles between the Russian and Ottoman Empires in the Black Sea region still shape Western perceptions about the relations between Moscow and Ankara today. Some experts therefore con­sider their current partnership to be “a historical anomaly”. Such a view – and the expectations associated with it – ignore the dynamics of the relations between Moscow and Ankara after the collapse of the two empires and also underestimate the signifi­cance that the Montreux Convention still has for Turkey. With the 1936 Convention, Turkey secured sovereignty over the Bos­porus, the Sea of Marmara and the Darda­nelles. The document not only regulates access through the straits, but also the length of stay of warships – and thus the military balance – in the Black Sea.

Ankara regards the Montreux Convention to be an instrument of regional secu­rity, intended to serve not only its own interests but also those of neighbouring and non-riparian states. This was most recently demonstrated by the way Ankara invoked the Convention on 28 February 2022, four days after the start of the war in Ukraine. Referring to Article 19, which concerns the passage of warships of bellig­erent actors, the then Turkish Foreign Min­ister, Mevlüt Çavuşoğlu, stated that Turkey “warned all riparian and non-riparian countries not to let warships go through the straits”. This was Ankara’s response to Ukraine’s demand that the straits be closed to Russian warships, while at the same time minimising the potential for escalation.

The geostrategic importance of the Black Sea region

The centuries-old trade routes through the Black Sea and along its coasts have made the region a strategically important hub between the eastern edge of Europe and the Caucasus as well as the foothills of Asia. As a result of European sanctions against Russian fossil fuels, the area around the southern Black Sea has become a major hub for these important raw material exports for Russia.

At the same time, the entire Black Sea region is also the focus of the Chinese Belt and Road Initiative (BRI), the so-called New Silk Road, because trade routes to Europe, the Mediterranean and North Africa cross the region. In particular, the trade route to Europe runs either through the Black Sea or through the littoral states to Eastern Europe. Here, the BRI trade routes also cross Russian natural gas and oil pipelines.

This geostrategically important region west of the Black Sea is also known as the Intermarium. Between the Baltic Sea and the Adriatic lie small and medium-sized Eastern European countries that in the past often had to assert themselves between the great powers of Europe and Russia. During the Cold War, most of these countries were under the influence of Soviet foreign and security policy. Today, many of them are members of NATO and the European Union (EU) and are seeking a greater say in the Black Sea region through the Three Seas Initiative.

Last but not least, the Black Sea region is the setting for several territorial and ethnic conflicts, such as Transnistria in Moldova, South Ossetia and Abkhazia in Georgia, and the dispute between Azerbaijan and Arme­nia over Karabakh. These tensions have existed since the collapse of the Soviet Union and have come to play an increasing role in the West’s relations with Russia over the years. From Moscow’s point of view, these regions form a geostrategic buffer zone that it secures through a military presence. The West, in its turn, devotes its attention to the post-Soviet conflict areas mainly in the context of its Russia strategy. The confrontation between Russia and NATO thus has a direct impact on these conflicts, which prevents the formation of a functioning security architecture.

Russia’s actions in the Black Sea

Since the annexation of Crimea in 2014, Moscow has upgraded the peninsula with military capabilities in line with the bastion concept. This is intended to enable Russia to meet and effectively combat potential threats in locations far from its territory. To this end, the Russian Federation has not only expanded powerful early warning and weapon systems on land, but also equipped its Black Sea Fleet with long-range land- and sea-based missiles. With the military capa­bilities it has accumulated since 2014, Moscow has once again signalled its claim to supremacy in the region with great strength; at the same time, it is also exert­ing pressure on the other riparian states.

In its maritime doctrine of 31 July 2022, Russia declared the Black Sea and the ad­jacent Sea of Azov as important areas of national interest. The region thus has the same rank as the Baltic Sea and the Medi­terranean. This classification refers to all military and civilian policy fields, that is, to aspects of security as well as to questions of prosperity, economic development, etc. The Russian Black Sea Fleet in particular is of great importance to Russia. It has a special significance as an instrument of Russian foreign and security policy and an enforcer of maritime doctrine. The Black Sea Fleet is one of four Russian naval fleets. Its mission is the regional projection of power and it serves as an essential launching point for Russia’s military activities in the Mediterranean and the Middle East. Beyond the Bosporus, it regularly receives support from units of the Baltic Fleet, the Northern Fleet and occasionally the Pacific Fleet. This inter­action of Russian fleets makes it clear that the Kremlin views the geographic region from the Arctic and the North Atlan­tic to the Baltic and the Black Sea as a single geostrategic entity. The use of different resources – whether political, diplomatic, military or economic – is part of a com­mon strategic context.

The war in Ukraine has also significantly changed the risk and threat situation in the Black Sea. In addition to the continued militarisation of the region, especially by Russia, it is above all the effects of aggres­sion in violation of international law that are generating new threats and lines of conflict. Civilian shipping and commercial traffic are now concentrated in the triangle between the Bosporus, the Romanian Danube Delta and the Russian port city of Novorossiysk. Only occasionally are ships underway in the area of southern Ukraine or at the entrance to the Sea of Azov. The important sea routes within the Black Sea are much more under threat and fragile as a result of the war. For much of 2022, ship movements along the Romanian and Bul­garian Black Sea coasts were also severely restricted due to occasional sightings of floating mines. These were anchor mines torn loose from Ukrainian coastal waters. Armed forces of both parties are believed to have laid such mines there. Due to their age, lack of technical maintenance and adverse weather conditions, mines have broken loose and in some cases drifted as far as the entrance to the Bosporus. They posed an unpredictable threat to civilian navigation and had to be located and de­fused in a joint effort by Turkish, Bulgarian and Romanian forces.

Relevance for NATO

Since the adoption of its new Strategic Con­cept at the Madrid Summit in June 2022, NATO has explicitly designated Russia as the greatest threat to Euro-Atlantic security. In particular, the militarisation of maritime spaces pursued by Moscow is a cause for concern from the Alliance’s point of view. The Black Sea region is of strategic impor­tance for the security of the Alliance and its partners.

In direct response to the annexation of Crimea in 2014, NATO and several Western allies unilaterally increased their presence in the region. Since then, Allied aircraft have been patrolling the airspace over the Black Sea, Romania and Bulgaria as part of NATO’s “Air Policing” mission. After the NATO summit in Warsaw in 2016, the “Tailored Forward Presence” was established on land in Romania and Bulgaria. With the decisions of the Madrid Summit in 2022, these elements form the basis for the Alliance’s recently established Battle Groups in Romania, Bulgaria and Hungary. Under the NATO flag, these multinational troop contingents are intended to strengthen the Alliance’s core mission of deterrence and defence. This has tripled the number of US troops in Romania, among other places, from about 1,000 soldiers in January 2022 to about 3,000 today. With the troop con­tingents of the mobile 101st Airborne Divi­sion, the Americans have not only deployed highly trained and combat-ready units to a particularly exposed Romania, but are also using their presence and proximity to the fighting in Ukraine for continuous recon­naissance and information gathering. To this end, drones are also regularly deployed in international airspace over the Black Sea. Romania has currently become the lynch­pin of the Allied and American presence in the Black Sea region and the measures initiated there to increase NATO’s deterrence and defence readiness.

In the maritime domain, the Alliance’s operations in the region have largely come to a standstill since the outbreak of Russia’s war in Ukraine and the entry into force of the restrictions imposed by Turkey on navigation of the Bosporus. Apart from the Bulgarian, Romanian and Turkish units stationed in the Black Sea, there are no longer any external Allied naval forces in the Black Sea, as has been the case almost continuously since 2014. Alliance manoeuvres and exercises also no longer take place at sea.

One of NATO’s core concerns following the decisions of the Wales Summit in 2014 was to take greater account of the Black Sea region in its own planning and to establish military security structures there. A Black Sea Coordination Function was supposed to be established at the Alliance’s maritime headquarters in Northwood, United King­dom, to coordinate operations and exer­cises. The aim was to provide the means for a continuous picture of ship movements and a better overall understanding of devel­opments in the region. In 2016, Bulgaria proposed to transfer this maritime coordi­nation function from Northwood to a “Regional Naval Coordination Presence” in Varna. The proposal received broad support among member states – only Turkey re­jected the initiative, so the decision is still pending. Ankara’s aim has been to limit the influence of external actors in the region, especially the non-regional Allies and the Alliance as an organisation, thus strengthening its own position in the Black Sea region.

Turkey’s interests

Turkey has two concerns in the Black Sea region: First, the government in Ankara has been keen to avoid provoking Russia. Sec­ond, it is concerned about asserting its own leadership in the region vis-à-vis NATO. When the United States sought to extend NATO’s Active Endeavour maritime sur­veil­lance operation from the Mediterranean to the Black Sea in 2005, it was met with strong resistance from Ankara, which argued that NATO already had a sufficient presence in the region with Turkey as an Ally.

To ensure security in the Black Sea, Turkey has initiated its own naval regional cooperation schemes. In 2001, it established the Black Sea Naval Cooperation Task Group, the BlackSeaFor. The main task of this cooperation project, which includes all six Black Sea littoral states, has been to con­duct joint naval exercises and carry out rescue operations and humanitarian missions. In 2004, Turkey launched a national operation, Black Sea Harmony, to improve mari­time surveillance in its own Black Sea waters and counter possible terrorist threats. The Turkish government has since invited all littoral states, including Russia, to partici­pate in this mission and the structures set up for it. Officially, Russia has participated in Black Sea Harmony since 2006. With the multinational opening of the operation, the accompanying protocols declared con­fidence-building and increasing maritime security in the Black Sea to be the main tasks of the cooperation format.

As well as seeking a leading role as a NATO member in the Black Sea, the Turkish government is also concerned with limiting the presence of the United States. What is particularly problematic for Ankara is not NATO’s presence in the region as such, but the effects of US policy on Turkey. This re­lates to Turkey’s experiences with US secu­rity policy in the Middle East. As a result of the US intervention in Iraq in 1991, the Iraqi Kurds established an autonomous area in the north of the country, which posed a security problem for Turkey. In 2003, Ankara denied American units the use of military bases in connection with the sec­ond war in Iraq. Turkey has regarded US policy in the Middle East as a source of instability, not only for itself but also for the South Caucasus. In August 2008, after the outbreak of the war between Georgia and Russia, Ankara prevented the US Navy hospital ships USNS Mercy and USNS Comfort from entering the Black Sea. Today, Tur­key’s bi­lateral relations with the United States are also under great strain. Both Ankara and Washington see each other as challenging their regional interests, be it in the Middle East, the Eastern Mediterranean or the Black Sea region. Not least because of his, Turkey is pursuing its own path among the NATO states, which is evident in the Black Sea region.

After Russia’s annexation of Crimea in 2014, Turkey did not join the Western sanctions against Moscow, but nevertheless initiated military cooperation with Ukraine. Its goal was not only to close the gaps in its own production capacities, but also to increase Ukraine’s military capabilities. In Turkey’s ideal of regional order, Ukraine plays an essential role in containing Russian hegemonic claims. Against this backdrop, a trade and arms cooperation has developed that benefits both sides. In 2015, Turkey delivered its first shipments of military ammunition to Ukraine. In 2016, Ankara and Kyiv signed an agreement on strategic cooperation in the defence industry. And in 2019, both sides concluded a deal on the delivery of Turkish drones to Ukraine.

Before the start of the war in Ukraine on 24 February 2022, Turkey’s policy was large­ly in line with NATO’s approach to­wards Russia, namely deterrence and dia­logue. Unlike the Alliance, Ankara still adheres to this approach today. Staying in dialogue with Russia has allowed Turkey to establish itself as a mediator between Moscow and Kyiv. Especially with the efforts around the Black Sea Grain Initiative in the summer of 2022, Ankara held the hope that this could be a step towards a ceasefire. The adherence to this balance between deter­rence and dia­logue vis-à-vis Russia is thus not only due to the special bilateral rela­tions with Moscow.

Since 24 February 2022, Turkey has not moved closer to the West as expected, but has expanded its relations with Russia. The war in Ukraine has undoubtedly increased Ankara’s value for Moscow as well. This applies above all to trade relations and the energy sector. In October 2022, for exam­ple, Vladimir Putin made an offer to Recep Tayyip Erdoğan at their meeting in Astana to build a gas hub in Turkey. Whether this idea, which Ankara has long dreamed of, is feasible remains unclear, but the Turkish side is well aware of its own value to Russia. Thus, the Erdoğan government may expect the postponement of gas payments to Gaz­prom – amounting to US$ 20 billion – to 2024 and a 25 per cent discount on the gas price. Cooperation in the field of nuclear energy in particular has become one of the most important pillars in Turkish-Russian relations. Ankara’s interest in this energy source dates back to the 1960s. The in­auguration of the Akkuyu Nuclear Power Plant, built by Rosatom, on 27 April 2023 was celebrated in Turkey as a “step into the global nuclear league”. The plant is ex­pected to provide 10 per cent of Turkey’s electricity needs.

Although the opposition parties in Tur­key criticise their country’s economic dependence on Russia, they too see func­tioning relations with Moscow as essential, “if not by choice, then by obligation”. This view is reflected in public opinion in Tur­key. In a survey commissioned by the Euro­pean Council on Foreign Relations, 55 per cent of respondents in Turkey consider Russia a necessary partner, 14 per cent an ally with shared values and interests, 18 per cent a rival and 8 per cent an adversary.

Turkish-Russian concept of order for the Black Sea region

Since 24 February 2022, all forms of coop­eration between the West and Russia have come to a standstill in many European maritime spaces. Not only has the West applied economic and political sanctions in response to Russia’s breach of international law, but all trust in Russia has been shaken for decades to come. This applies to the challenges posed by climate change, eco­nomic cooperation, fisheries protection, ter­ritorial disputes, aspects of the security of civil maritime traffic as well as to questions of arms control and security policy in insti­tutional and bilateral agreements. Neither in the Arctic nor in the Baltic Sea will the above-mentioned tasks be handled jointly with Russia – the largest country in the Eurasian region in terms of area – in the foreseeable future.

In the Black Sea, the situation is different. Here, great power ambitions meet regional ideas of order. From the perspective of Western analysts, the Black Sea pre­sents a “black hole” or “murky waters”. For Ankara and Moscow, on the other hand, the Black Sea region represents a kind of informal condominium. Thus, since the end of the Cold War, there has been a shared understanding between the two on what the regional order should look like. Both Russia and Turkey consider the Black Sea as a zone of privileged interests, where­by no presence of external actors is desired. This view is reminiscent of Carl Schmitt and his remarks on “the Grossraum order with a ban on intervention by powers for­eign to the region (raumfremde Mächte)”. In a concerted action – at least not offi­cially, but recognisably – Turkey and Russia have together established a regional arrangement in the Black Sea, making it de facto a (joint) Mare Clausum. By mutual agreement and in a constant interplay of their own inter­ests, the Black Sea has become a region controlled, dominated and cordoned off by Russia and Turkey.

Today’s perception of relations between Ankara and Moscow is dominated by the leadership diplomacy between Erdoğan and Putin. On the one hand, this is not without reason. A lot can be settled through direct, personal communication, as evidenced, for example, by the telephone calls with which the two presidents negotiated the passage of Turkish ships in the Sea of Azov in March 2022 to avoid shortages of sunflower oil in Turkey. With Russia largely isolated from the West, Putin is also keen to further cement ties with Turkey under Erdoğan, who the Kremlin chief once described as “not only pleasant but also safe” to deal with.

But in the Black Sea region in particular, one constant can be observed that endures beyond personal relationships. Control over the straits has been a perennial point of contention in the history of Russian-Turk­ish relations. Since the beginning of the 20th century, however, the struggle between the two has not been about supremacy. The competitive relationship still exists, but the priorities for both actors are to maintain the power balance in the Black Sea region, secured by the Montreux Con­vention, and to limit the military presence of Western actors. Against this backdrop, the Ukrainian desire to make the Black Sea more of a NATO-controlled sea area is not feasible in the foreseeable future. Turkey, in particular, is likely to stick with its regional ideas of order for the Black Sea region.

Outlook and recommendations

The Russia-Turkey partnership is close, but it is not an alliance. For Russia, Turkey remains first and foremost a NATO mem­ber. From Moscow’s point of view, the coun­try on the Bosporus is a player to be taken seriously, precisely because of its NATO membership. In its balancing act between deterrence and dialogue towards Russia, the former is no less important to Turkey than the latter. Although Ankara has a tradition of denying US warships access to the Black Sea, it also supplies fuel to US aircraft in the region. When Ukraine sought corvettes with sea-launched missiles to strengthen its fleet in 2019 and did not get what it wanted from the United States and the United Kingdom, Turkey was will­ing to sign a deal. Before the war, the US expert community was concerned whether the defence relationship between Turkey and Ukraine would go beyond merely deter­ring Russia and have the potential to pro­vide Moscow with a casus belli. Turkey does not perceive itself as being threatened, even after the Russian attack on Ukraine, but other threat perceptions prevail. Ankara also sees the risk level of a possible confron­ta­tion between Russia and NATO as low, since it has its own bilateral relations with Moscow.

Against this background, the Turkish-Russian relationship can best be understood as a functional and transactive community of purpose. This often follows a pragmatic willingness to cooperate, depending on the situation. The goal of this mutual relationship is to preserve the Black Sea as an en­closed space, as a Mare Clausum, in the sense of their own regional concepts of order. At the same time, NATO remains an important fallback position for Turkey to counter Russian aspirations for influence and in the event that relations with Moscow deteriorate significantly. Within NATO, Tur­key uses its special role and its own relations to make its voice heard in the West. Tur­key’s foreign and security policy thus re­sembles a pendulum that swings back and forth between the two poles of deterrence and dialogue vis-à-vis Russia. Depending on the situation, the pendulum always tilts most strongly in the direction from which the greatest political gain can be made.

At the same time, Russia’s war in Ukraine offers Turkey the opportunity to use the Montreux Convention in the sense of its own perception of order and to mar­ginalise the presence of NATO, the United States and other actors, at least in the mari­time area. In Turkey’s security policy think­ing and actions, Western values take a back seat to its own regional interests. This is un­likely to change in the foreseeable future.

NATO’s presence in the Black Sea region – and with it the focus of Allied deter­rence and defence measures against Russia – will be concentrated on Romania and Bulgaria. However, the transatlantic Alli­ance would be well advised not to stigmatise Turkey as a troublemaker and to take advantage of Ankara’s regional conceptions and interests. By giving Turkey more re­spon­sibility in shaping security structures, the Black Sea region could be stabilised in the medium term and frictions minimised. With regard to NATO, it would be con­ceivable for Turkey to take the lead in the regional coordination function. Other Allied neighbours, such as Bulgaria and Romania, could be assigned tasks to clear sea mines or monitor trade routes due to their prox­imity and current security threats. This would accommodate Ankara’s ideas and interests in the region, but at the same time involve Turkey more closely again in the implementation of measures to strengthen NATO’s deterrence and defence capabilities. The necessarily greater integration of Ukraine into the European security archi­tecture, which could take a step forward at the upcoming summit in Vilnius in the form of a more realistic NATO accession prospect, will also have an impact on the future regional order in the Black Sea.

The Turkey-led Black Sea Grain Initiative, agreed in July 2022, illustrates that Ankara is an indispensable actor in the region. A Black Sea governance structure based on minilateralism – beyond NATO or the EU – may have the greater potential to engage both Kyiv and its security interests as well as Moscow, following a cessation of Russian aggression. Turkish initiatives such as BlackSeaFor and Black Sea Harmony could be developed into a permanent regional structure dedicated to non-military, but nevertheless security-relevant, aspects in the Black Sea region, such as sea rescue, the fight against organised crime and the con­sequences of environmental pollution as well as fisheries protection.

Göran Swistek is a Visiting Fellow in the International Security Division at SWP.
Daria Isachenko is an Associate at the Centre for Applied Turkish Studies (CATS).

The Centre for Applied Turkey Studies (CATS) is funded by Stiftung Mercator and the German Federal Foreign Office.

© Stiftung Wissenschaft und Politik, 2023

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This Comment reflects the authors’ views.

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Stiftung Wissenschaft und Politik

German Institute for International and Security Affairs

Ludwigkirchplatz 3–4
10719 Berlin
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ISSN (Print) 1861-1761

ISSN (Online) 2747-5107

DOI: 10.18449/2023C33

(English version of SWP‑Aktuell 36/2023)