The Geopolitical Trilemmas of the Ponto-Baltic Axis

Vasile Simileanu, PhD geopolitics

Abstract: The geopolitical trilemmas along the Ponto-Baltic axis, sharpened by the Russia–Ukraine war, revolve around three fundamental tensions: maximum military security versus the risk of escalation and economic costs; energy independence versus the exposure of new infrastructure to hybrid attacks; and allied cohesion versus divergent national interests. On the Black Sea, Romania confronts the dilemma between support for Ukraine and its own vulnerability, between the development of the Neptun Deep project and its protection, as well as between the demand for a stronger NATO presence and Turkey’s preference for regional ownership. Turkey manages the tension between NATO loyalty and strategic autonomy, maintaining pragmatic relations with Russia and control of the straits under the Montreux Convention. Poland, although focused on the Baltic, must balance its northern priority with north–south strategic continuity and support for Ukraine with its own rearmament resources. Within the Bucharest Nine format, the trilemmas are amplified by the conflict between the group’s political unity and internal divergences in the perception of the Russian threat, between the vision of a security continuum from the Black Sea to the Arctic and sectoral north–south priorities, as well as between increased European responsibility and dependence on the United States. These tensions admit no simple solutions, and the practical responses—trilateral demining cooperation, fortifications on the Baltic, pragmatic partnerships and coordination within the B9—represent only attempts to manage them, not to eliminate them.

Keywords: Ponto-Baltic axis, geopolitical trilemmas, NATO eastern flank, Black Sea, Baltic Sea, Bucharest Nine (B9) format, Poland.

The Ponto-Baltic axis—the strategic corridor linking the Black Sea (Pontus Euxinus) to the Baltic Sea—has become, after Russia’s full-scale invasion of Ukraine in February 2022, the principal line of contact in the confrontation between Moscow and the West. It is no longer a European periphery but a space where military security, energy independence, global grain trade and the cohesion of alliances intersect. In this context, the states and seas of the region face real geopolitical trilemmas: how to strengthen deterrence without provoking nuclear escalation; how to reduce dependence on Russia without creating new economic vulnerabilities; and how to maintain NATO/EU unity while national interests diverge (from Poland and Romania, direct front-line states, to Turkey, which controls the straits).

These trilemmas are not abstract. They translate into concrete risks for populations: hybrid attacks on critical infrastructure, disruptions of wheat exports that affect food prices in Africa and the Middle East, or the everyday fear of residents in the Baltic states and on the Romanian coast that a “false-flag” incident or a stray drone could trigger Article 5.

The Baltic Sea: From “NATO Lake” to Hybrid Warfare Theatre

After the accession of Finland and Sweden, the Baltic Sea has frequently been described as a “NATO lake.” Reality is more nuanced. Russia retains access through Saint Petersburg and the Kaliningrad exclave, an A2/AD (anti-access/area denial) fortress armed with missile systems and electronic warfare capabilities. Since 2022, Moscow has intensified hybrid operations: sabotage of undersea data and energy cables, manoeuvres by the “shadow fleet” of tankers that evade sanctions, and drone or aircraft incursions that test the Alliance’s reaction.

For the littoral states the trilemma is clear: maximum security versus economic costs and the risk of escalation. Poland has responded with the East Shield programme, a network of fortifications and obstacles along approximately 700 km of border with Belarus and Kaliningrad, together with naval modernisation (frigates, Swedish submarines) and increased defence spending. Polish ports (Gdańsk, Gdynia, Świnoujście) and the LNG terminals plus the Baltic Pipe have become vital for the energy independence of Central Europe, reducing dependence on Russian gas.

The Baltic states (Estonia, Latvia, Lithuania) are constructing the Baltic Defence Line, a defensive line stretching over 1,600 km designed to buy time for the mobilisation of allies. The principal vulnerability remains the Suwałki Corridor—the roughly 65 km that link Lithuania to Poland and separate Kaliningrad from Belarus. Closure of this corridor would isolate the Baltic states. In 2025–2026, intelligence warnings from the region concerning possible Russian provocations (including “false-flag” operations involving Ukrainian drones) have prompted increased protection of energy and civilian infrastructure.

From a human perspective, the inhabitants of Tallinn, Riga or Gdańsk live with the awareness that their geography—flat terrain, short distances—offers no strategic depth. The war in Ukraine has demonstrated that a Russian army can advance rapidly across open ground; consequently, deterrence by denial (preventing occupation) has become priority over deterrence by punishment.

The Black Sea: Fulcrum of European Security and of Global Food Security

If the Baltic is the northern flank, the Black Sea is the southern pivot of the axis. The war has militarised the basin: the Russian fleet has suffered heavy losses from Ukrainian drones and missiles, yet has continued to threaten commercial navigation with mines, drones and attacks on ports. Ukraine has achieved a “silent reconquest” of grain export routes, using the territorial waters of Romania and Bulgaria and the port of Constanța as an alternative hub after the collapse of the Black Sea Grain Initiative.

After February 2022 the Black Sea moved from a relatively marginalised space in Euro-Atlantic strategy to a fulcrum of European security. Here three critical dimensions intersect: control of maritime routes (grain, energy, trade), military deterrence vis-à-vis Russia, and the management of relations with regional actors whose interests diverge. In this context Romania, Poland and Turkey are not mere littoral or allied states but nodes of specific geopolitical trilemmas: how to strengthen the NATO presence without forcing a militarisation that would violate the Montreux regime; how to exploit offshore energy resources without exposing infrastructure to hybrid attacks; and how to maintain the unity of the eastern flank (from the Baltic to the Black Sea) while national interests and degrees of exposure differ radically.

Romania: Exposed Southern Frontier and Emerging Energy Pivot

Romania occupies the most vulnerable and, simultaneously, the most promising position on the western shore of the Black Sea. With a land border of roughly 650 km with Ukraine and a coastline of 245 km, Bucharest has become, since 2022, an essential logistical hub for Ukrainian grain exports (via Constanța and the Danube corridor) and a major NATO military node. The Mihail Kogălniceanu base has been transformed into a major operational and logistical centre on the south-eastern flank, and Romania hosts a multinational brigade led by France.

The trilemma here is triple: maritime security, energy and regional cohesion. Offshore gas reserves (Neptun Deep in Romania, Sakarya in Turkey) can reduce Europe’s dependence on Russia, yet platforms and undersea cables are hybrid targets. Romania has become an essential logistical hub—facilitating the transport of tens of percent of Ukrainian grain—and a NATO military node (the Mihail Kogălniceanu base is expanding). At the same time it has recorded multiple violations of its airspace by Russian drones, some of which have reached its territory.

The Romanian trilemma is acute along three axes:

Security versus support for Ukraine. Romania has recorded dozens of airspace violations by Russian drones (25 in the first eight months of 2026 alone), some of which reached its territory and caused civilian casualties. The response has been pragmatic: legislative changes to permit the downing of drones, acquisition of anti-drone systems (including the US-produced Black Talon, tested and scheduled to become operational by the end of 2026 at the military ports of Constanța, Mangalia, Tulcea and Brăila) and repeated calls for a NATO mission of the “Black Sea Sentry” type that would redistribute radars, missiles and anti-drone systems on the southern flank.
Energy versus vulnerability. The Neptun Deep project (approximately 100 billion cubic metres of recoverable gas) reached decisive stages in 2026: the Neptun Alpha production platform was installed, pipelines are being laid, and commercial production is scheduled for 2027. Once operational, the project would double domestic gas production and make Romania the largest producer in the EU, contributing to regional energy independence (including deliveries to Moldova and interest from Germany and Slovakia). At the same time, offshore platforms and pipelines are ideal targets for hybrid attacks; in July 2026 Romania downed unauthorised drones near the project area.
Allied presence versus regional ownership. Bucharest has consistently advocated a more robust NATO naval presence in the basin, yet confronts Ankara’s reservations about a “NATO-isation” that could undermine the Montreux regime. The pragmatic solution has been trilateral cooperation with Turkey and Bulgaria: the Mine Countermeasures Black Sea Task Group, launched in 2024, has neutralised more than 150 mines and was expanded in July 2026 (at the NATO summit in Ankara) to include protection of critical undersea infrastructure (energy, telecommunications, pipelines).

Romania thus plays the role of the “southern anchor” of the eastern flank: sufficiently pro-Atlantic to demand greater allied presence, sufficiently pragmatic to build partnerships with Turkey, and sufficiently exposed to feel the consequences of the war on its own skin.

Turkey: Indispensable Gatekeeper and Source of Strategic Autonomy

Turkey is the actor without which no Black Sea security architecture can function. It controls the straits under the Montreux Convention (1936), possesses the longest coastline, the second-largest army in NATO and an expanding defence industry. The 2022 decision to close the straits to the warships of the belligerents drastically limited Russia’s ability to reinforce the Black Sea Fleet and allowed Ukraine to reduce significantly the Russian naval threat.

The Turkish trilemma is profound:

Alliance versus autonomy. Ankara remains a NATO member and has intensified trilateral cooperation with Romania and Bulgaria, including the export of ships (in 2026 Romania received a MILGEM-class corvette). At the same time it maintains open economic and diplomatic channels with Russia (trade, energy, mediation) and promotes the doctrine of “regional ownership”: security of the basin must be managed primarily by the littoral states, not through a massive naval presence of non-littoral powers.
Security versus economic interests. Turkey mediated the Grain Initiative and contributed decisively to demining, yet refuses to align fully with sanctions, which allows it to play a pivot role but generates tensions with European partners.
Deterrence versus escalation. Through control of access and through its military capabilities, Turkey is the most credible deterrent against a Russian return to naval hegemonic status. At the same time, full alignment with an aggressive NATO strategy would reduce the manoeuvring space Ankara has constructed over the past two decades.

For Romania the partnership with Turkey has been strategic for fifteen years and has intensified since 2022. For Poland the relationship has deepened through a defence memorandum (2025) and through Poland–Turkey–Romania trilateral dialogues. Turkey thus becomes the “southern pillar” of the eastern flank, complementary to Poland (north) and Romania (centre-south).

Turkey occupies the key position. Through the Montreux Convention (1936) it controls the Bosporus and Dardanelles straits. In 2022 it closed access to the warships of the belligerents, severely limiting Russia’s capacity to reinforce the Black Sea Fleet. Ankara mediated the Grain Initiative and maintains a pragmatic dialogue with Moscow (trade, energy) without renouncing its status as a NATO member. This “strategic autonomy” creates a trilemma for the West: how to integrate Turkey more deeply into the Black Sea security architecture without accepting its claims to regional “ownership” and without pushing it toward a more pronounced equidistance.

Trilateral cooperation among Turkey, Romania and Bulgaria on demining (Mine Countermeasures Black Sea Task Group) was expanded in 2026 to the protection of critical undersea infrastructure—a concrete example of a regional response. Without Turkey, no Black Sea security strategy is viable.

Poland: North–South Connector and Champion of Flank Unity

Poland has no Black Sea coastline, yet its role in the basin’s trilemmas is real and growing. Warsaw has been, since 2022, the principal logistical hub for Western assistance to Ukraine and one of the most vocal advocates of a unitary approach to the eastern flank—from the Baltic to the Black Sea. Formats such as the Bucharest Nine, expanded with the Nordic countries, and dialogues with Turkey and Romania reflect this vision: the Russian threat does not stop at Suwałki or Kaliningrad but extends as far as Odesa and Constanța.

The Polish trilemma related to the Black Sea is more indirect, yet relevant:

Concentration on the Baltic versus continuity of the flank. Poland’s absolute priority remains north-eastern defence (East Shield, naval modernisation, Nordic cooperation). Nevertheless, Warsaw understands that a Russian victory or consolidation of Moscow’s presence in the Black Sea would allow Russia to redistribute resources northward and create a corridor of instability through the Balkans.
Support for Ukraine versus own resources. Poland has provided substantial military assistance and hosted refugees, yet must balance this effort with its own rearmament needs.
New partnerships versus Euro-Atlantic tradition. The defence memorandum with Turkey (2025) and the trilateral dialogue with Romania demonstrate a pragmatic openness toward actors that can complement the NATO effort on the southern flank.

Poland thus functions as a “strategic connector”: it links Baltic concerns with Ponto-European ones and presses for a unitary approach to the flank in which Romania and Turkey are not treated as a southern periphery.

Poland and Romania: Anchors of the Eastern Flank

Poland has become, through the size of its army, its defence spending (among the highest in NATO as a percentage of GDP) and its geographic position, the northern anchor of the flank. Force modernisation, the East Shield programme and intensified cooperation with the Nordics and Baltics reflect the lesson of Ukraine: “fight tonight”—the capacity to fight immediately, not after months of mobilisation.

Romania plays a symmetric role on the southern flank. Its size, location (long border with Ukraine, Black Sea coastline) and transatlantic credibility transform it into a military and energy hub. Investments in Neptun Deep and naval cooperation with Turkey (including the acquisition of corvettes) demonstrate a pragmatic orientation. Both countries confront the same trilemma: how to support Ukraine (weapons, logistics, training) without exhausting their own stocks and without provoking a direct Russian reaction on their territory.

Common Trilemmas and Implications

The three states confront, to differing degrees, the same structural Black Sea trilemma:

Maximum security versus the risk of escalation (greater NATO presence vs. respect for Montreux and avoidance of a naval “arms race”).
Energy independence versus exposure (exploitation of Neptun Deep and other deposits vs. protection of critical infrastructure against hybrid attacks).
Allied cohesion versus national autonomies (unity of the eastern flank vs. the distinct interests of Turkey as pivot, Romania as front-line state and Poland as northern anchor).

The most realistic response, already visible in 2025–2026, is not a single solution but a layered architecture: littoral trilateral cooperation (Turkey–Romania–Bulgaria) for demining and infrastructure protection; NATO presence on land and in the air (brigades, air-policing, bases); bilateral and trilateral partnerships (including Poland–Turkey–Romania); and accelerated energy development accompanied by protective measures.

From a human perspective these trilemmas translate into concrete realities: farmers and operators in Constanța who depend on secure export routes, coastal residents who hear drone alarms, and citizens in Poland who understand that their long-term security also depends on the stability of the Black Sea. Romania, Poland and Turkey are not merely actors on a geopolitical map; they are the countries that, through their pragmatic choices, decide whether the Black Sea remains a space of prolonged confrontation or becomes a stable pillar of European security.

The Bucharest Nine (B9) Format

The Bucharest Nine (B9) format, launched in November 2015 at the initiative of the presidents of Romania and Poland, brings together nine states on NATO’s eastern flank: Bulgaria, Czechia, Estonia, Latvia, Lithuania, Poland, Romania, Slovakia and Hungary. Created in reaction to the annexation of Crimea, B9 evolved after 2022 into a political and strategic caucus that seeks to transform the eastern flank from a “periphery” into a centre of gravity of the Alliance. Recent summits, especially that of 13 May 2026 in Bucharest (co-hosted by Romania and Poland, with the participation of the Nordic countries, the NATO Secretary General and the President of Ukraine), confirmed a new paradigm: the eastern flank is treated as a strategic continuum from the Black Sea to the Arctic, passing through the Baltic.

This evolution does not eliminate the trilemmas; it amplifies them and makes them more visible. B9 confronts structural tensions that mirror, at regional scale, the broader dilemmas of the Ponto-Baltic axis.

The first trilemma is that of internal cohesion: Political unity versus divergences in the perception of the threat

The Baltic states, Poland and Romania perceive Russia as an existential long-term threat, which leads them to demand high defence spending (the 5 % of GDP target reaffirmed in Bucharest), permanent allied presence and unconditional support for Ukraine. By contrast, Hungary maintains a more favourable position toward Moscow and is critical of support for Kyiv, while Czechia, Slovakia and Bulgaria often adopt a more ambivalent attitude, influenced by domestic factors, historical energy dependencies or economic priorities.

This division affects B9’s capacity to speak with a single voice within NATO. At the 2026 summit the final declaration succeeded in designating Russia explicitly as the principal long-term threat and in reaffirming support for Ukraine, yet the price was a formulation that took account of the sensitivities of the various capitals. The trilemma is clear: forced unity risks diluting the message and reducing the format’s influence; open divergence undermines its credibility as the “voice of the eastern flank.”

The second trilemma concerns the north–south balance: Geographic continuity versus sectoral priorities (Baltic versus Black Sea)

The Bucharest summit underlined the “security continuum” from the Black Sea to the Arctic, recognising that hybrid threats, drone incursions, sabotage of critical infrastructure and military pressure are interconnected. In practice, however, the Nordic and Baltic states (together with Poland) concentrate resources on the Baltic Sea (Baltic Sentry, East Shield, defence of Suwałki), while Romania and Bulgaria insist on equal attention to the Black Sea—demining, protection of energy infrastructure (Neptun Deep), air defence and a possible “Black Sea Sentry”-type mission.

Romania, as co-founder and host of the 2026 summit, used the format to anchor the Ponto-European dimension in the broader flank agenda. Without this pressure the risk would be that the Black Sea remains a “secondary dossier.” The trilemma consists in maintaining a unitary vision of the flank without neglecting the specific character of each sea: the Baltic, more “closed” and more easily treated as a “NATO lake” after the accession of Finland and Sweden, versus the Black Sea, regulated by the Montreux Convention and dependent on cooperation with Turkey.

The third trilemma concerns resources and burden-sharing: European responsibility versus dependence on the United States and national resources

B9 has become a vocal supporter of increased defence spending and of the development of the European industrial base, conscious that the American presence on the eastern flank may be reassessed. Member states commit to ambitious targets (5 % of GDP), yet industrial and budgetary capacities differ dramatically: Poland and, to a lesser extent, Romania and Czechia can absorb major investments, while smaller states or those with domestic political constraints (Hungary, Slovakia) face limits.

The format attempts to resolve this tension through coordination—information exchange, interoperability, joint missions (Eastern Sentry, support for Ukraine) and collective pressure on Western allies. Nevertheless the trilemma remains: accelerated Europeanisation of flank defence (greater autonomy) may reduce dependence on the United States, yet risks creating temporary capability gaps; maintenance of strong dependence on Washington provides short-term credibility but leaves B9 vulnerable to oscillations in American policy.

The Role of Romania, Poland and the Link with Turkey in the Logic of B9

Within B9, Poland and Romania play the roles of natural co-leaders. Poland brings military weight, size and the northern vision; Romania brings the Ponto-European dimension, front-line experience on the Black Sea and the capacity to dialogue with Turkey. The 2026 summit illustrated this complementarity: the Romanian–Polish co-presidency explicitly linked the Black Sea to the Baltic and the Arctic, preparing positions for the NATO summit in Ankara.

Turkey is not a member of B9, yet its influence is felt indirectly. Trilateral cooperation among Turkey, Romania and Bulgaria on demining and critical infrastructure is an example of “regional ownership” that complements, without replacing, B9 efforts. The Bucharest Nine thus becomes a space in which Black Sea littoral states can articulate the need to integrate Turkey into a wider architecture without forcing a naval “NATO-isation” unacceptable to Ankara.

Implications and Limits

B9 has demonstrated that it can function as a multiplier of influence: it has contributed to the expansion of the allied presence on the flank, to the increase in defence spending and to the legitimation of the idea of a north–south strategic continuum. Nevertheless, the internal trilemmas—unity versus divergences, geographic balance, resources versus ambitions—limit its potential. Long-term success depends on the capacity to manage these tensions without allowing them to dilute the collective message.

From a human perspective, B9 is not merely a diplomatic forum. It is the platform through which the most exposed states attempt to transform the lessons of the war in Ukraine—vulnerability of infrastructure, the importance of air defence against drones, the necessity of military mobility—into concrete policies. For the inhabitants of Tallinn, Warsaw, Bucharest or Sofia, the success or failure of this format translates into the degree of security they will feel in the coming years. The continuum from the Black Sea to the Baltic already exists on the map; B9 seeks to make it real on the ground as well.

Conclusions: A Unified Axis, Persistent Trilemmas

The war in Ukraine has demonstrated that NATO’s eastern flank can no longer be treated in isolated segments. From the Baltic Sea to the Black Sea there exists a strategic continuity: the same hybrid threats, the same infrastructure vulnerabilities, the same resource dilemmas. Formats such as the Bucharest Nine, expanded with the Nordics, or trilateral cooperation in the Black Sea show an awareness of this reality.

The trilemmas remain: security versus prosperity, deterrence versus the risk of escalation, European autonomy versus dependence on partners (the United States, Turkey). The most realistic response is not a single solution but a combination of fortification (East Shield, Baltic Defence Line), energy diversification (LNG, offshore gas, interconnections), pragmatic regional cooperation (Turkey–Romania–Bulgaria) and the maintenance of support for Ukraine as an advanced defence line.

For the people who live along this axis—from the farmers of Dobrogea to the inhabitants of Gdańsk or Constanța—the stakes are not theoretical. They concern everyday safety, the price of food and energy, and the hope that the lessons of the war in Ukraine will be transformed into credible deterrence, not into a new tragedy. The Ponto-Baltic axis has ceased to be a map; it has become a living theatre of European security.

The fundamental tension remains that between the need for strong military deterrence and the risk of escalation, between energy independence and the exposure of new infrastructure, as well as between allied unity and divergent national interests. On the Black Sea, Romania, Turkey and Poland illustrate these dilemmas in concrete forms: Bucharest must balance support for Ukraine with its own vulnerability and the development of energy resources with their protection; Ankara plays the role of pivot between NATO loyalty and strategic autonomy; and Warsaw links Baltic priorities with north–south strategic continuity. The Bucharest Nine format amplifies these tensions through the conflict between the group’s political unity and internal divergences, as well as through the difficulty of maintaining a real security continuum from the Black Sea to the Arctic. Overall, the trilemmas cannot be eliminated, only managed through pragmatic cooperation, regional coordination and a combination of fortification, energy diversification and flexible partnerships that transform the lessons of the war in Ukraine into credible deterrence without provoking a new crisis.

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