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Europe’s most fragile region is not sleepwalking toward war, but it is quietly recalibrating for it. Across the Western Balkans, military procurement decisions once framed as technical upgrades are evolving into something more consequential: a shifting balance of power unfolding at a moment when Europe’s security order strains under growing transatlantic tension. 

These regional dynamics emerged unevenly, with Serbia clearly leading the way a decade ago. In response, neighboring countries have also modernized their militaries, though in different ways. NATO members such as Albania, Montenegro, and North Macedonia have focused primarily on meeting alliance capability and interoperability benchmarks. Fellow NATO ally Croatia’s modernization is similarly shaped by alliance requirements, but also by acute insecurity stemming from Serbia’s “greater state” ambitions and its rapid militarization. Meanwhile, non-NATO members Bosnia and Herzegovina and Kosovo are navigating more autonomous and regional sensitive calculations. The collective result is not imminent war, but a complex environment shaped by uneven capabilities, alliance asymmetries, and competing political narratives. These factors define the strategic context in which military modernization is now unfolding. While the region is probably not returning to the conflicts of the 1990s, a security dilemma is emerging without clear guardrails: Defensive measures by one state can inadvertently heighten insecurity for others.

This matters now because the conditions that once dampened escalation are weakening. External security guarantees feel less automatic, and deterrence signals are increasingly inconsistent. Russia’s war in Ukraine has unsettled assumptions about restraint, borders, and the costs of using force. In this environment, militarization does not require aggressive intent to become destabilizing. Misperception, asymmetric capabilities, and narratives that frame force as legitimate can trigger crises faster than political institutions can respond. NATO and EU leaders should therefore push for greater confidence-building measures and political transparency across the region.

A Postwar Balkans in Transition

After the disastrous ethnic wars of the 1990s, the Balkans were defined by cautious disarmament and arms control, externally guaranteed peace, and reliance on international oversight. The wars left behind unresolved ethno-territorial disputes that continue to shape security perceptions. Most prominently, Serbia does not recognize Kosovo’s independence, while Bosnia and Herzegovina remains internally fragmented along ethno-political lines under the Dayton framework. Although large-scale violence ended decades ago, disputes over sovereignty, minority protection, and borders persist, making military signaling unusually sensitive. These unresolved legacies mean that even defensive force development is often interpreted through the lens of past conflict rather than as purely technical modernization. Indeed, conflict history remains central to how regional states interpret military signals and assess risk.

Relations between Serbia and Kosovo remain complex more than two decades after the 1998 to 1999 war. While Serbia does not recognize Kosovo, the two countries have agreed to a dialogue facilitated by the European Union — although its implementation has been characterized by half-measures and violations. Periodic crises ranging from disputes over governance in northern Kosovo to violent incidents involving security forces have prevented full normalization. Despite the EU dialogue and NATO’s longstanding peacekeeping mission in Kosovo, relations remain fragile and prone to escalation.

Since the 1990s, most Balkan countries have prioritized economic recovery and institutional development over military capability. Full NATO integration became the principal security anchor for Albania, Croatia, Montenegro, and North Macedonia, shaping each country’s respective defense modernization within an alliance framework. For its part, Serbia navigated a more complex path, balancing regional dominance ambitions with ties to Moscow, Beijing, and later Europe. Bosnia and Herzegovina and Kosovo aspire to join NATO but face distinct structural and political constraints that limit the pace and scope of their modernization.

From 2000 to 2015, Serbia maintained significant latent capability, including heavy armor and air defense systems, inherited from the Yugoslav era. After 2015, Serbia shifted from latent capability to active modernization, largely unnoticed by outside observers. Indeed, despite steadily rising defense spending, European Commission annual country reports on Serbia did not acknowledge the upward trend until 2020, when Serbia’s military spending was noted to have increased by nearly 30 percent year-on-year and procurement from Russia and China was first explicitly referenced. Serbia’s approach emphasized legacy strength, selective modernization, and procurement diversification — a formula that positioned the country as the region’s first mover in military development.

Serbia: Strategic Buildup and Procurement Diversification

Serbian leaders frame this modernization as a response to a deteriorating regional security landscape. Official narratives frequently cite NATO’s expansion in southeast Europe, Kosovo’s alignment with Western security structures, and the long-standing presence of NATO forces in Kosovo and Bosnia and Herzegovina as evidence of strategic constraint. From Belgrade’s perspective, diversification of suppliers and investment in advanced capabilities are required to preserve autonomy and freedom of action.

Serbia’s buildup began around 2015 with increased investments in combat aircraft, air defense, armored vehicles, drones, and electronic warfare. Its defense budget exceeded two billion dollars annually by the mid-2020s, or roughly 2.5 percent of GDP. This acceleration occurred after key regional states had already joined NATO (Hungary in 1999; Romania and Bulgaria in 2004; and Croatia and Albania in 2009). Montenegro and North Macedonia joined NATO later (2017 and 2020, respectively), after Serbia’s trajectory was already underway. Importantly, Serbia’s National Security Strategy and Defense Strategy do not stipulate NATO enlargement in the Balkans as a primary reason for militarization. In fact, Serbia has maintained formal engagement with NATO through the Partnership for Peace program and an Individual Partnership Action Plan, underscoring a multi-vector effort rather than outright confrontation.

Serbia’s procurement strategy reinforced its intent to shape the regional military balance in support of its political goals. Serbia acquired Israeli precision-strike and surveillance technologies and French Rafale fighter jets, while maintaining Russian and Chinese systems. Unlike NATO members, whose modernization is largely guided by alliance interoperability requirements and collective defense obligations, Serbia’s approach reflected independent strategic priorities.

In parallel with military modernization, Serbian leaders have projected political narratives emphasizing the protection of co-nationals living abroad — mainly in Kosovo, Bosnia, and Montenegro — and historical grievances related to loss of territory and control. While signaling defensive intent domestically, such framing shaped regional perceptions and heightened sensitivity to Serbian military moves. This combination of public framing and growing capabilities made neighbors acutely aware that misjudging Serbia’s intentions could carry real risks.

Serbian political ambition and decisive action intersected in Sept. 2023, when heavily armed men crossed from into northern Kosovo, killing a police officer and leaving behind armored vehicles and weapons. Investigations traced equipment and training back to Serbia. This was not an isolated incident. It followed repeated increases in Serbian troop presence along the Kosovo border during periods of heightened tension, moves that repeatedly triggered regional and international concern. While Belgrade denied direct involvement, the incident illustrates how the margin for error has narrowed. Even minor miscalculations can escalate quickly, reinforcing the security dilemma that defines regional dynamics.

Neighboring States: Reactive Modernization

Serbia’s military buildup has prompted a series of nationally distinct military modernization responses across the region. These responses are not the product of collective planning or coordination, but of parallel national decisions shaped by various factors, including alliance status, domestic constraints, and differing threat perceptions.

Albania accelerated efforts to meet NATO capability benchmarks of investing 2 percent of GDP annually in defense by 2024, directly influenced by Serbia’s growing air and missile capacity. The country’s planners prioritized air defense, artillery modernization, and mechanized units capable of countering regional power asymmetries. Albania also hosts NATO investments and infrastructure upgrades, with modernization efforts designed to strengthen national defense readiness while remaining aligned with alliance capability and interoperability requirements. 

Croatia has modernized within the NATO framework, acquiring Rafale fighters, Bradley infantry vehicles, and Black Hawk helicopters. The country has also has ordered Leopard 2 tanks, Bayraktar drones, and High Mobility Artillery Rocket Systems. These acquisitions aimed to maintain parity in regional air and mechanized power, ensuring Croatia could match Serbia’s enhanced capabilities while remaining interoperable with NATO forces. Defense plans have emphasized readiness and operational flexibility, reinforcing credibility without destabilizing the region. Croatia’s defense modernization also aligns with broader EU security objectives, illustrating how alliance membership shapes procurement and planning.

Rather than large-scale modernization, both Montenegro and North Macedonia have focused on resilience — ensuring their forces can operate effectively within a NATO framework and under shifting regional conditions shaped by an emerging arms race. Montenegro has emphasized rapid reaction forces and joint training, while it has purchased two French patrol boats. North Macedonia has pursued modernization in line with alliance benchmarks, acquiring mechanized units and enhancing air surveillance capabilities. It has ordered U.S.-made joint light tactical vehicle and Stryker combat vehicles, Italian helicopters (four AW149 and four AW169M), Turkish 105 mm Boran howitzers, and the French short-range air defense system Mistral 3. 

Kosovo, lacking NATO membership, has expanded the Kosovo Security Force under NATO supervision. The country has focused on building a credible, visible deterrent capable of rapid response to cross-border incursions. Planners explicitly considered Serbia’s military superiority when shaping Kosovo’s doctrine, training, and procurement. Kosovo has invested in drones and domestic ammunition production, enhancing strategic autonomy. Every decision — from unit size to equipment choice — reflected the idea that Serbia’s growing military power had narrowed Kosovo’s margin for error.

Bosnia and Herzegovina has responded more cautiously to defense surges in the region, increasing spending incrementally while prioritizing readiness, NATO interoperability where feasible, and training. Constrained by internal political fragmentation, the country has focused on command-and-control improvements and NATO-aligned exercises. 

For the non-NATO states in the region, namely Kosovo and Bosnia and Herzegovina, the military build-ups present a classical security dilemma: Defensive measures taken under uncertainty can heighten perceptions of insecurity for others in the absence of security guarantees. NATO members, by contrast, are embedded in a collective defense architecture and their modernization is driven primarily by alliance capability and interoperability requirements. That said, national force planning within NATO has increasingly factored in Serbia’s expanding air, missile, and armored capabilities and the resulting shifts in the regional military balance.

Defense Industry, Strategic Autonomy, and External Influence

Beyond force posture and procurement, the Western Balkans’ defense surge is increasingly shaped by the revival of domestic defense industries and the growing role of external suppliers.

National defense industries are reemerging as strategic tools. Serbia’s Yugoimport SDPR spans ammunition, artillery, armored vehicles, and unmanned systems, backed by state-supported exports and domestic investment. Croatia’s industry, though smaller, aligns with NATO standards, focusing on modernization, maintenance, and interoperability. Bosnia and Herzegovina specializes in ammunition and artillery production, signaling growth potential if political constraints ease. Albania, Kosovo, and Croatia have begun joint projects such as the Shota Mine-Resistant Ambush-Protected vehicle, reflecting a regional move toward selective self-reliance and sustainment capacity.

External powers shape the strategic environment. Russia, China, Turkey, and Gulf states offer arms and advisory services. Serbia retains strong ties with Russian and Chinese suppliers, while Albania and Kosovo benefit from NATO assistance and Turkish drone technology. These competing influences complicate interoperability, increase uncertainty, and reinforce the region’s security dilemma.

Industrial expansion can strengthen conventional deterrence while complicating signaling. Greater domestic production and procurement autonomy reduces vulnerability to external shocks, yet rapid militarization without transparency can escalate crises. These dynamics underscore that military modernization in the Western Balkans is no longer only a national matter. Managing its risks depends on deliberate policy choices about transparency, coordination, and external engagement that can either stabilize the region or allow misperceptions to harden. 

Policy Implications and Strategic Choices

While a Western Balkans arms race is well underway, it reflects preparation, not panic. Serbia’s early militarization set the tempo. Non-NATO neighbors such as Bosnia and Kosovo responded cautiously to manage regional risk, while NATO members modernized according to distinct alliance benchmarks and interoperability standards.

A politics of restraint is required to break the cycle of military build-ups and reduce the risk of miscalculation and escalation. Concrete confidence-building measures including expanded military-to-military communication — specifically, advance notification of major exercises, participation in transparency mechanisms, and greater disclosure of procurement plans — could help. Moreover, NATO can play a role by reinforcing deconfliction norms with non-member states, while the European Union can use accession conditionality to incentivize transparency and restraint. Without such measures, military modernization, however defensive in intent, could continue to generate mutual suspicion and escalation risks in the region.

Both NATO and EU leaders have emphasized that normalization between Serbia and Kosovo is essential to long-term regional stability, particularly given the alliance’s presence in Kosovo and neighboring member states. The European Union wields political and economic leverage primarily through conditionality, linking Serbia’s integration prospects to normalizing ties with Kosovo while geopolitically and economically pivoting from Russia. For its part, Washington views Balkan stability as integral to broader European security, recognizing that misperception or unchecked militarization could create vulnerabilities exploitable by external powers.

Europe and the United States should maintain a clear understanding of Balkan military developments and how imbalances could affect stability. Accountability in this context means adherence to alliance standards for NATO members, transparency obligations for non-members, and restraint in political and military signaling across the region. Without these guardrails, modernization risks reinforcing insecurity rather than deterrence. 

The Western Balkans will maintain stability only under disciplined transparency and measured military modernization. Otherwise, miscalculation and misinterpretation could generate new crises among old neighbors that could quickly spin out of control.

Blerim, Vela, Ph.D., served as chief of staff to the president of Kosovo from 2021 to 2023 and was a member of Kosovo’s National Security Council. He holds a doctorate in contemporary European studies and writes on governance, defense, and security in southeast Europe.

Image: Unknown author via Wikimedia Commons