The Bucharest 9 format emerged in 2015 as a Romanian-Polish initiative designed to give political coherence to the states on NATO’s Eastern Flank, at a moment when Russia’s aggression against Ukraine had already fundamentally altered security perceptions across Central and Eastern Europe. In its original logic, the B9 was a useful instrument: an informal regional platform through which the states most exposed to Russian pressure sought to coordinate their positions ahead of major decisions within the Alliance. Its central role was to build political capital inside NATO and support a more robust deterrence posture on the Eastern Flank, not to create an autonomous military mechanism, as the German Marshall Fund shows.
At precisely this point, the first misconception that any serious analysis must correct becomes clear: expanding a political format does not, in and of itself, expand security. For nearly a decade, the real strengthening of the Eastern Flank has not been produced by diplomatic formulas, but by concrete NATO decisions: enhanced forward presence, regional plans, air and missile defence, maritime activities, cyber protection, integrated exercises and, more recently, initiatives such as Eastern Sentry, explicitly presented by NATO . NATO states clearly that it has reinforced its deterrence and defence posture across the entire Eastern Flank, “from the Arctic Ocean in the north to the Black Sea in the south,” through combat-ready forces and the most extensive defence plans since the end of the Cold War.
The serious question, therefore, is not whether the B9 can become broader, but whether such enlargement produces any tangible security gain where it actually matters: in the number and quality of capabilities, in response times, in military mobility, in reinforcement logistics, in air defence, in interoperability and in the defence industrial base. If the answer is negative, enlargement remains above all a political signalling exercise, not a substantive strategic shift.
The Real Danger of a Poorly Calibrated Expansion
The fact that the B9 and Nordic countries summit, held in Vilnius on 2 June 2025, brought together the leaders of the Eastern Flank and the Nordic states already points to the direction in which the issue is evolving: there is a clear willingness to deepen cooperation between the Alliance’s two wings, and the subject is legitimate, according to the Romanian Presidential Administration and NATO . Following Finland’s and Sweden’s accession to NATO, Europe’s security architecture has been reconfigured, and the connection between the Baltic, the Arctic and the Black Sea has become tighter than ever. The problem, however, is that this strategic reality has already been incorporated at Allied level. NATO now operates with an overarching view of the entire Eastern Flank, from north to south. The broader framework already exists. That is why the risk is that any further expansion of the B9 would merely duplicate politically an architecture that NATO has already begun to address institutionally and militarily on a continental scale.
For Romania, the stakes are even more specific. Bucharest has an obvious interest in preserving its profile as a co-initiator and a relevant political node on the Eastern Flank. But a broader format does not automatically translate into a stronger position. On the contrary, it may dilute Romania’s precise priorities. The Nordic states enter the discussion with a strong strategic focus on the Arctic, the North Atlantic and Baltic maritime security. Romania, by contrast, has a vital interest in the Black Sea region, in the equation of southern Ukraine, in the vulnerabilities of the Republic of Moldova, in military mobility along the southern axis and in strengthening support infrastructure on the Alliance’s south-eastern segment. The more heterogeneous the political weight of the format becomes, the more difficult it becomes to keep the Black Sea at the centre of the agenda.
That is the real danger of an expansion that is difficult to calibrate properly: not lack of visibility, but loss of focus. A format created to articulate the specific voice of the East may end up functioning as a broader, more prestigious and more photogenic platform, yet one that is more diffuse in its priorities. More cautious communiqués, more difficult consensus, ambition lowered to the level of the smallest common denominator: these are the concrete risks of a larger geometry without firmer political discipline.
The criticism cannot be dismissed. Some recent analyses argue that the B9 already suffers from divergent strategic perceptions among its members and that adding new states with their own priorities does not solve this problem but complicates it. Even if such readings should not be absolutised, they begin from a valid observation: the political cohesion of an informal format becomes more fragile as the spectrum of strategic interests grows wider, as New Eastern Europe notes and, from another angle, the German Marshall Fund also suggests. A mechanism that functions on the basis of coordination and consensus does not automatically become more effective simply because it gathers more actors around the table.
There is also another problem, less spectacular but far more important: security on the Eastern Flank is now being decided in the realm of implementation, not in the invention of formats. Romania itself offers a telling example. The Ministry of National Defence presented the multinational exercise Dynamic Front 26 as a practical implementation of the Eastern Flank Deterrence Line and as an exercise within NATO’s regional plans, integrating land, air, maritime, cyber and space effects. This is where the difference between rhetoric and substance becomes visible. What raises the level of security is not the expansion of a diplomatic circle, but the ability to turn the region into a credible space of integrated defence, with command and control, interoperability and real response capacity.
In this respect, Romania needs a colder and more precise strategy. Bucharest should not treat any eventual expansion of the B9 as a success in itself. Real success must be measured in outcomes for the southern segment of the Eastern Flank: greater Allied attention to the Black Sea, accelerated investment in military and dual-use infrastructure, better logistical connectivity, more robust air and anti-drone defence, stronger relevant command structures and tighter integration between NATO planning and national capabilities. If expanding the B9 does not deliver such results, it remains an image asset, not a strategic multiplier.
There is, of course, a legitimate counterargument. A broader B9, or one more clearly anchored in a B9-plus-Nordics format, could increase the region’s political critical mass inside NATO and the EU, could better connect the north and south of the Flank, and could make Eastern priorities harder to ignore in the internal competition for resources. Theoretically, that argument makes sense. In practice, however, its effectiveness depends on a hard condition: the new format must not become too broad an umbrella to produce operational clarity. In security matters, expanded representation is not always an advantage; at times, it is merely an elegant way of masking dispersion.
For Romania, the balance is already sufficiently clear. The first trap is that of prestige: the illusion that a larger format automatically means greater status and, by extension, greater security. The second is the trap of passivity: the assumption that NATO will, on its own, resolve the imbalances between the northern and southern parts of the Eastern Flank. In reality, if Romania does not systematically push the Black Sea dossier, it risks remaining secondary in a conversation increasingly dominated by the Baltic, the Arctic and northern Europe.
In addition, such an enlarged format could acquire relevance in another, far more sensitive register, even if it is rarely formulated publicly in these terms: that of a potential reduction in the American commitment to Europe. The issue is not officially embraced in B9 rhetoric, but it has already entered the Allied strategic debate, against the backdrop of increasingly visible discussions about the need for Europe to shoulder more of the burden of deterrence and defence. Reuters reported that Ankara had urged Allies to prepare for a possible reduction in US participation in the Alliance, while Secretary General Mark Rutte spoke as early as February about a NATO that would become more European-led while maintaining a strong American presence, again according to Reuters . In this context, the real question for the states on the Eastern Flank is not only whether the B9 can become larger, but whether it can contribute politically to preparing the region for a scenario in which the United States does not formally leave NATO, but gradually reduces its practical involvement in Europe.
The B9 has had, and still has, its utility. As an instrument of consultation, as a platform for coordination and as an expression of regional solidarity, it remains relevant. But precisely because it remains relevant, it should not be burdened with expectations it cannot fulfil. Security on the Eastern Flank comes from military power, planning, infrastructure, defence industry, strategic coherence and the political will to prioritise the most vulnerable areas. Expanding the B9 may be diplomatically useful, but it should not be mistaken for a strengthening of defence. The problem is not a lack of formats. The problem is whether the states on the Eastern Flank, and Romania above all, can turn political attention into concrete strategic guarantees. Otherwise, the Eastern Flank will continue to look good in summit photographs while remaining insufficiently convincing in the hard calculations of deterrence.
