Romania’s Role in the Security Architecture from the Baltic to the Black, Caspian and Adriatic Seas
By Lieutenant (ret) General Corneliu Pivariu
The concept of Intermarium—originally conceived by Józef Piłsudski[1] during the interwar period—envisioned the creation of a confederation of states between the Baltic, the Black and the Adriatic Seas, capable of counterbalancing both Germany and Russia. Although the historical project never materialised, it periodically resurfaces in geopolitical analyses, especially in the context of the fragile security architecture of Central and Eastern Europe.
Today, through the Three Seas Initiative (3SI)[2], the Bucharest Nine (B9)[3], and under the pressure of the war in Ukraine, the idea of Intermarium gains renewed relevance, extending as far as the Caspian area, where energy and transport corridors link Europe to the Caucasus and Central Asia.
Although the Intermarium concept continues to be invoked in contemporary strategic analyses, in its historical form it remains more of a theoretical exercise; nevertheless, the idea of strengthened cooperation among the states between the Baltic, the Black and the Adriatic Seas continues to inspire regional initiatives with evolutionary potential.
Regional Strategic Context
The Baltic–Black–Caspian–Adriatic region forms a geopolitical arc of contact between NATO/the EU and the Russian sphere of influence. It includes:
- The eastern flank of NATO – from the Baltic States to Romania and Bulgaria;
- Energy and transport corridors – including Caspian routes, gas pipelines, and maritime and land interconnections;
- The Western Balkans and the Adriatic – where the competition for influence between the West and Russia overlaps with China’s interests in infrastructure.
This area concentrates both vulnerabilities and opportunities:
- vulnerability to Russian pressure (military, hybrid, and energy-related);
- the importance of east–west and north–south transport corridors;
- the position as a bridge towards the Middle East and Central Asia.
The Economic Dimension of Cooperation within the Intermarium Space
Although the Intermarium project was originally conceived as a political–military framework for balancing great powers, the realities of the 21st century require an expansion of the concept to include economic, energy, and logistical dimensions.
In this sense, the Three Seas Initiative (3SI) represents the most practical expression of the Intermarium logic, offering an institutional framework for cooperation among the states of Central and Eastern Europe in infrastructure, energy, and digitalisation[4].
Along this north–south axis—between the Baltic, the Black and the Adriatic Seas—a range of concrete projects is taking shape, capable of turning the region into an economic and energy corridor of strategic importance:
- *Rail-2-Sea – the proposed railway connection between the ports of Gdańsk and Constanța;
- *Via Carpatia – a transregional motorway linking Lithuania to Greece;
- *The BRUA Corridor – a gas transport infrastructure connecting Bulgaria, Romania, Hungary, and Austria;
- *LNG terminals in Poland and Croatia supporting energy diversification in the region;
- *Amber Rail Freight Corridor, later integrated into the Baltic–Adriatic Corridor, designed to streamline freight transport along the north–south axis.
Although these initiatives are in various stages of implementation, they express a clear trend towards functional regional integration, beyond military and political convergences. Their purpose is to reduce dependence on the traditional west–east infrastructure historically dominated by Germany and Russia, offering an economic alternative aligned with Euro-Atlantic strategic interests.
The NATO Dimension
For NATO, the Intermarium is synonymous with the Eastern Flank[5]. From the Baltic States—exposed to Russian military pressure—to the Black Sea, where the Alliance’s interests directly clash with Moscow’s, the region represents the contact line between two antagonistic geopolitical worlds.
Initiatives such as the Bucharest Nine (B9) or the strengthening of NATO’s forward presence in Poland and Romania demonstrate that the security of this region is a priority. However, the diversity of national interests means that the unity of the eastern flank remains more a declarative than a real objective.
The Russian Dimension
For Russia, the Intermarium represents a Western-imposed “sanitary cordon” meant to restrict its access to Central Europe and the Balkans. The Kremlin perceives any strengthening of cooperation among the Baltic, Black, and Adriatic Seas as a direct threat.
In this sense, the war in Ukraine is also a battle to prevent Ukraine from becoming a pillar of a new Intermarium. Moscow seeks to counteract it through a strategy of destabilisation: maintaining frozen conflicts (Transnistria, Abkhazia, South Ossetia), using propaganda, and exploiting energy dependencies. Moreover, the Kaliningrad[6] enclave plays an important role in this regard.
The Great Powers and the Intermarium
The United States supports the consolidation of the eastern flank and the Three Seas Initiative, seeing in the Intermarium a means to anchor regional allies and reduce energy dependence on Russia. Washington encourages investments in infrastructure, energy, and defence, treating the region as a vital bastion of the transatlantic order.
Germany and France regard the Intermarium idea with reserve, fearing that it could compete with the EU. However, in order not to let the US gain exclusive influence, they have accepted the Three Seas Initiative. France focuses on the Mediterranean and Africa, while Germany seeks control over critical European infrastructure.
Russia views the Intermarium as a structure of isolation, which fuels its anti-Western discourse.
China does not involve itself directly in regional security, but expresses interest through the Belt and Road Initiative, investing in ports, railways, and energy to strengthen its economic presence.
Thus, the great powers project their own interests onto the Intermarium, turning the region into an arena of emerging multipolarity.
Romania – A Geostrategic Pivot
Romania’s position is essential for any Intermarium project:
- The Black Sea[7]: Romania is NATO’s main littoral state, responsible for securing this strategic area. The Bosporus and the energy routes from the Caucasus increase Romania’s strategic relevance.
- The Carpathians and the Balkans[8]: Romania links the northern flank (Poland and the Baltic States) with the southern one (the Balkans and the Adriatic). North–south corridors and trans-Carpathian infrastructures are of vital importance.
- Resources and Infrastructure[9]: Romania is an active participant in the Three Seas Initiative and can capitalise on energy projects (Black Sea gas, interconnections with Azerbaijan and Georgia) as well as infrastructural ones (motorways, railways, digital networks).
The opportunities for Romania lie in strategic visibility, attracting investments, and consolidating energy security. Yet the risks are equally significant: Russian pressure, internal vulnerabilities (corruption, political fragmentation), and the danger of being caught between divergent interests (the US, Germany, France).
Challenges and Perspectives
The Intermarium space is marked by:
- lack of regional cohesion due to historical rivalries (Poland–Hungary, Croatia–Serbia, Romania–Hungary);
- the risk of being instrumentalised by the great powers, in the absence of an autonomous regional integration project;
- internal vulnerabilities such as political instability and governance issues, which limit Romania’s ability to act as a regional leader.
Conclusions
The Intermarium is not an alternative to NATO or the EU, but a complementary component that can strengthen the eastern flank and reduce structural dependencies. For Romania, it represents a dual challenge: managing geopolitical pressures while turning geographic vulnerability into strategic advantage.
The success of this project depends on:
- tangible support from the US and the EU for the Three Seas Initiative;
- Romania’s ability to modernise its infrastructure and armed forces;
- the resilience of regional states in the face of Russian pressure and the geopolitical temptations offered by China.
As mentioned at the beginning of this study, although the Intermarium concept continues to be invoked in contemporary strategic analyses, in its historical form it remains largely a theoretical exercise; nevertheless, the idea of strengthened cooperation among the states situated between the Baltic, the Black and the Adriatic Seas continues to inspire regional initiatives with genuine potential for evolution.
If Romania intelligently capitalises on its position as a pivot between the Black Sea, the Carpathians and the Balkans, it can move from the status of a vulnerable frontier to that of an indispensable actor within Europe’s security architecture.
Selective Bibliography
Historical and Foundational Sources
- Piłsudski, Józef. Political Writings. Documents on the Intermarium Project. Warsaw: Translated and Annotated Editions, 2005.
- Mackinder, Halford J. Democratic Ideals and Reality. Bucharest: Editura Militară, 1995.
- Brzezinski, Zbigniew. The Grand Chessboard: American Primacy and Its Geostrategic Imperatives. Bucharest: Univers Enciclopedic, 2000.
General and Contemporary Geopolitical Analyses
- Kaplan, Robert D. The Revenge of Geography. Bucharest: Litera, 2013.
- Friedman, George. The Next 100 Years: A Forecast for the 21st Century. Bucharest: Litera, 2011.
- Motyl, Alexander J. “Intermarium: Conceptualising a Geopolitical Space between the Baltic and the Black Seas.” East European Studies Journal, no. 2/2017.
- Chatham House. Russia, Ukraine and the Future of European Security. Reports 2022–2025.
- Council on Foreign Relations. Eastern Europe and NATO’s Frontier Security. Washington, 2023.
Institutional Documents and Initiatives
- NATO. Strategic Concept 2022. Brussels, 2022.
- European Union. Global Strategy for the European Union’s Foreign and Security Policy. Brussels, 2016.
- Three Seas Initiative. Summit Declarations (2016–2024). Warsaw, Bucharest, Tallinn, Sofia.
Romanian and Regional Contributions
- Pivariu, Corneliu. Geopolitical and Military Lessons from the Russia–Ukraine Conflict. Bucharest: Financial Intelligence, 2025.
- Pivariu, Corneliu. Global Geopolitical Developments in the First Quarter of the 21st Century. Romania in this Context. Forecasts for 2050. Bucharest: Financial Intelligence, 2025.
- Ioniță, Sorin. “The Three Seas Initiative and its Relevance for Romania.” Revista 22, no. 10/2019.
- Dungaciu, Dan; Rusu, Petrișor. The Black Sea: NATO and the EU on the Eastern Frontier. Bucharest: Tritonic, 2016.
- Chifu, Iulian. Geopolitics in the Extended Black Sea Region. Bucharest: Curtea Veche, 2018.
- European Institute of Romania. Studies on Strategy and Regional Security. Bucharest, 2020–2023.
Complementary Works and Reports
- International Institute for Strategic Studies (IISS). The Military Balance (Editions 2022–2025). London.
- RAND Corporation. Deterring Russia in the Baltics. Santa Monica, 2022.
- Atlantic Council. Three Seas Initiative: A Strategy for Transatlantic Unity. Washington, 2023.
[1] Józef Piłsudski (1867–1935), Polish statesman and military leader, promoted after the First World War the idea of a federation of states between the Baltic and the Black Seas (“Intermarium”), intended to balance the influence of Germany and Russia.
[2] The Three Seas Initiative (TSI) was launched in 2015 at the joint proposal of Poland (President Andrzej Duda) and Croatia (President Kolinda Grabar-Kitarović). It brings together 13 European Union member states located between the Baltic, Black, and Adriatic Seas, aiming to develop infrastructure, enhance energy and digital connectivity, and strengthen regional cohesion and security.
[3] The Bucharest Nine (B9) group was established in 2015 at the initiative of Romania (President Klaus Iohannis) and Poland (President Andrzej Duda). Comprising nine Eastern European NATO member states — Bulgaria, the Czech Republic, Estonia, Latvia, Lithuania, Poland, Romania, Slovakia, and Hungary — the group aims to coordinate regional positions on Euro-Atlantic security and to strengthen the Alliance’s eastern flank. The initiative enjoys consistent support from the United States and NATO and is regarded as a complementary instrument for enhancing allied unity and resilience.
[4] Although numerous projects have been proposed and several have already been implemented, critics point out that only a relatively small number have been completed so far — some reports note that only 14 of the 143 priority projects have been finalized (or have reached an advanced stage of implementation). Major obstacles include high levels of bureaucracy, difficult cross-border coordination, divergent national priorities, the lack of a strong central implementation mechanism, and dependence on EU or external funding. Although the 3SI was conceived as a framework for coordination among states on regional projects, it lacks strong executive mechanisms in itself — its success lies rather in the fact that governments have begun to design major projects from a regional perspective.
[5] The term “eastern flank” is the established NATO formulation which, from a military standpoint—as I have noted on other occasions and as other prominent military analysts have also stated—is a political definition rather than a militarily accurate one. In fact, it should be referred to as the “eastern front,” a formulation that could gradually gain acceptance if Russia continues its aggression in Ukraine.
[6] Kaliningrad is an enclave of the Russian Federation located on the Baltic Sea coast, between Poland and Lithuania. A former German territory (Königsberg) annexed by the Soviet Union in 1945, the region holds exceptional strategic importance as Russia’s westernmost military base. It hosts the headquarters of the Baltic Fleet and a dense complex of A2/AD (Anti-Access/Area Denial) capabilities, including Iskander-M ballistic and anti-ship missile systems, S-400 and Bastion systems, as well as aviation and electronic warfare units.
Its position enables control over maritime and air routes across northern Poland and the Baltic states, serving as a major leverage point against NATO. Since 2022, Moscow has strengthened its military presence in Kaliningrad, expanding ammunition storage infrastructure and intensifying joint exercises with the Baltic Fleet, accompanied by rhetoric about the potential deployment of tactical nuclear weapons.
[7] Romania holds a geostrategically vital position on the Black Sea, located at the intersection of economic, energy, and military corridors linking Central Europe, the Caucasus, and the Middle East. The Port of Constanța, the largest port on the Black Sea and one of the most important in Europe, functions as the main logistical hub of the European Union’s and NATO’s eastern flank.
Through its rail and river connections (via the Danube–Black Sea Canal), the port provides direct access to the European transport network (TEN-T), serving as the natural terminus of the Rail-2-Sea project and as a key link in the north–south interconnection axis promoted by the Three Seas Initiative. At the same time, the port serves as critical infrastructure for allied mobility within NATO, holding strategic value comparable to that of the ports of Gdańsk and Koper.
[8] Romania occupies a unique geographical and strategic position at the confluence of the Carpathian arc and the Balkan sphere of influence, forming a natural link between Central and South-Eastern Europe. The Carpathian mountain chain, which crosses its territory for more than 900 km, provides a distinctive defensive terrain while granting control over the main access routes from Pannonia, Ukraine, and the Black Sea.
Situated north of the Balkans, Romania serves as a bridge between the Danubian–Carpathian area and the Balkan Peninsula, playing a role of regional stability and strategic continuity within the European security architecture.
Its geographic position enables Romania to become the connecting element between the northern and southern segments of the Intermarium axis, thereby strengthening the geopolitical relevance of the region within the broader Euro-Atlantic framework.
[9] Romania possesses significant potential in natural and energy resources, including substantial reserves of natural gas (both onshore and offshore in the Black Sea), crude oil, coal, non-ferrous ores, as well as considerable hydroelectric and agricultural resources. The development of gas exploitation projects in the Neptun Deep and Midia Gas Development perimeters strengthens its role as a regional energy producer.
From an infrastructural standpoint, Romania is crossed by the main European transport corridors (TEN-T), connecting the Black Sea with Central and Western Europe through railway, road, and river networks (including the Danube–Black Sea Canal).
This combination of resources and infrastructure makes Romania an essential energy and logistical pillar of the European Union’s and NATO’s eastern flank, while also providing economic and strategic support for the regional projects of the Three Seas Initiative and the broader Intermarium concept.
Nevertheless, the national infrastructure remains affected by structural and investment gaps, an insufficiently modernized transport network, and partial dependence on energy imports—factors that currently limit the full exploitation of its strategic potential.
“Between empires and alliances, the lands between the Baltic and the Black Seas have always been less the masters of their own destiny and more the arena where destinies are decided.”
— (attributed to George F. Kennan, paraphrased from American Diplomacy)
