EU security in the Western Balkans

The EU’s security policy has helped maintain peace in the Western Balkans since the early 2000s, but institutional reforms remain incomplete and external actors are gaining ground. This piece examines where the EU’s efforts have succeeded, and where they have fallen short.

For decades, the region of South-Eastern Europe, now more commonly referred to in today’s EU terminology as the Western Balkans, has represented both a strategic, though rather volatile frontier of Europe. The Western Balkans today comprises Albania, Bosnia and Herzegovina (BiH), Kosovo, Montenegro, North Macedonia, and Serbia – neatly grouped together as the ‘Western Balkans 6’ (or ‘WB6’). This specific region has been shaped in recent years by its post-conflict and a post-communist legacy and enduring ethnic and political dynamics. Moreover, the region has found itself increasingly trapped in the middle of a delicate balancing act between rival geopolitical agendas – chief among them the European Union, Russia and the US. With Brussels seeking to cement the region firmly within its orbit and to support peace and stability in the region (and bring the WB6 fully into the Union as members), the EU has engaged a mixture of civilian and military instruments under the Common Security and Defence Policy (CSDP) framework.

This article examines how the EU’s security and defence policy has developed in recent years in the Western Balkans, evaluates its main missions and elements of its available toolbox, and assesses its success in meeting the complex challenges driven by competition, nationalism, and weak governance.

Why the Balkans matter to Brussels

The driving force behind EU involvement in the region is primarily based on geographic, historical, and strategic necessity. The Balkans lie at the crossroads of Europe and the wider Mediterranean periphery – always a corridor for commerce and trade, migration, ethnic and tribal rivalries and ultimately, conflict. After all, the violent break-up of Yugoslavia in the early 1990s bore witness to genocide in Bosnia and Herzegovina, along with ethnic cleansing throughout the region; these dynamics continue to shape how Brussels views the security of the region.

Back in 2003, at the EU Thessaloniki Summit, Brussels made an unambiguous and brave promise: all Western Balkan states were to be considered “potential candidates” for membership. However, EU accession remains elusive for most in the region. Instead, EU influence has largely operated through soft power mechanisms – conditionality, aid, and fragmented diplomatic engagement – but also through direct defence and security interventions under the CSDP framework. This dual-pronged approach – the offer of full membership alongside robust security collaboration – forms the foundation of EU policy in the Balkans. Yet the effectiveness of this architecture is now under scrutiny, especially as geopolitical competition intensifies.

EU security in action

The EU’s security presence in the Western Balkans has been delivered through both civilian and military engagement on the ground, as represented by the following missions.

EUFOR Althea

Today, the EU’s most visible military presence in the Western Balkans is EUFOR (EU Force) Althea, a CSDP operation launched in December 2004 following the withdrawal of NATO’s SFOR^[1] mission. SFOR followed on from the NATO IFOR mission^[2] that had been tasked with providing security on the ground as the first steps to implementing the Dayton Peace Accord took off.

EUFOR Althea, initially composed of roughly 7,000 troops drawn from a number of European armed forces (including France, Germany, Italy, Spain, Türkiye and the UK), still operates under an annually renewed UN Security Council mandate. However, EUFOR has since significantly reduced in numbers in recent years with its current tasks focusing more on training and supporting the Armed Forces of BiH and serving as a rapid reaction force in the event of unrest. The mission also supports Bosnia and Herzegovina’s path toward Euro-Atlantic integration and continues to act as a stabilising presence in the region. Today, 22 countries provide around 1,100 troops, currently under Romanian leadership, with Austria, Hungary and Romania the leading contributors.

The EUFOR mandate was renewed in November 2023 with increased troop numbers against the backdrop of heightened political tensions in the country, especially the divisive secessionist rhetoric coming from the Serb entity, Republika Srpska, and its increasingly belligerent president, Milorad Dodik. Critics argue that the current force is far too small and underequipped to meaningfully deter any large-scale violence or political destabilisation. Nevertheless, in the current fragile environment, even a symbolic European presence and boots on the ground carries strategic weight.

EULEX Kosovo

Launched in 2008, EULEX Kosovo represents the EU’s most ambitious rule-of-law mission to date. Upon its inception, its primary focus was to assist Kosovo in building a professional and fully functioning judiciary, police service, and customs authority. Initially intended as a hybrid mission with executive powers, it was foreseen that the mission would bring about legitimacy and strengthen the overall capacity of Kosovo’s new institutions.

However, EULEX has faced widespread criticism since the start, not least because its mandate has undergone repeated revisions, reducing the envisaged executive functions, with the advisory role the centre of its efforts. EULEX has been accused of being ineffective, untransparent, with only limited impact on the key mandate areas of tackling corruption or combatting organised crime. To make matters worse, a number of former EULEX prosecutors and officials have faced allegations of misconduct, leading to an issue of credibility.

 

Despite these failures, EULEX provides a stabilising role in a highly contested and complex political environment, especially in the northern part of Kosovo where Kosovo Serb resistance to Kosovar sovereignty remains entrenched and unbending. EU-led mediation in the Serbia-Kosovo dialogue, although largely political, is supported by EULEX’s local presence throughout the country.

Other civilian missions – high impact capacity-building efforts

The EU’s first-ever civilian crisis management CSDP operation, launched on 1 January 2003 was the European Union Police Mission (EUPM) in Bosnia and Herzegovina (2003–2012). The EUPM focused primarily on police reform and capacity building, taking over from the UN’s International Police Task Force (IPTF). The IPTF was seen as playing a decisive role in stabilising post-war BiH society and also played a role in assisting in the return of internally displaced persons and refugees prior to handing over to the EUPM.

Soon after its arrival, it was clear to the EUPM that its main objective of assisting local authorities in creating a durable, professional, and multi-ethnic police force operating under the rule of law would be far from an easy. The mandate provided to EUPM also included the promotion of police reform, enhancing inter-agency cooperation, and assisting local law enforcement as they began the task of combatting organised crime and corruption, both of which were rampant in the country post-conflict. The EUPM later shifted its focus to boosting the criminal justice system.

EU technical assistance and twinning projects have also been launched to reform judicial and administrative structures elsewhere in the region, namely in Montenegro, Serbia, and North Macedonia. These standalone initiatives, though less high-profile than the civilian crisis management and military missions, represent core components of the EU’s long-term strategy to build resilient institutions and bring Western Balkan states in line with the EU’s acquis communautaire.^[3]

EU efforts – evaluating success

As to whether the EU’s defence and security policy has been effective in the Western Balkans depends on the defined evaluation criteria—whether that’s the maintenance of peace, the strengthening of local institutions, or the enhancement of the EU’s credibility in the region.

Keeping the peace

To the EU’s credit, there has been no serious violence or armed conflict in the Western Balkans on its watch since the early 2000s. This traditionally volatile region of Europe is now largely peaceful–though far from out of the woods. The joint role of EU and NATO engagement on the ground can be thanked for this. For its part, although modest in both size and scope, EUFOR Althea continues to serve as a tangible stabilising presence in Bosnia and Herzegovina, while in Kosovo, EULEX, working alongside KFOR (NATO’s Kosovo Force), plays a key role in deterring a resurgence of violence in Kosovo.

However, the absence of conflict does not automatically equate to peace, since there are frequent (almost non-stop in some cases) political crises and tension between ethnicities remain; this is all not helped by the fact that several Western Balkan states (Bosnia and Herzegovina, Kosovo, and to some degree, North Macedonia) are still functionally fragile.

 

Rule of law and institutional reform: A mixed picture

The EU’s focus on rule of law and democratic reforms has met only limited success. The judiciary in Kosovo is weak, in spite of 17 years of EULEX engagement. Some progress can be noted, especially in North Macedonia, after it was forced to resolve its name dispute with Greece before joining NATO in 2020. The systemic and institutional reforms required by Brussels are frequently only implemented on a selective basis. Again, critics of EU efforts argue that engagement from Brussels carries limited leverage given that robust accession timelines are lacking, thereby diluting the EU’s transformative power of conditionality.

A question of EU credibility

Arguably the most disturbing trend in the Western Balkans for Brussels has been the gradual loss of EU credibility, as evidenced by widespread and very real enlargement fatigue among the region’s public and also in many capitals in Europe for that matter. An almost constant moving of the goalposts by the EU on accession timelines and conditionality, bi-lateral disputes delaying or event obstructing accession (see Slovenia with Croatia earlier on; and Greece and now Bulgaria with North Macedonia), it is hardly surprising if the wider public have become increasingly sceptical about EU membership. While Brussels delays, others are losing no time in stepping in – particularly Russia, China, and Türkiye. The clear case in point here is Moscow’s meddling in Republika Srpska (BiH), China’s impressive ‘Belt and Road Initiative’, and Türkiye’s cultural, religious and economic diplomacy; all contribute to the weakening of EU soft power in the region.

The EU’s credibility in the region is also related to a number of interrelated challenges. These include a lack of strategic coherence: EU foreign and security policy is not always communicated effectively. Conflicting member state interests – such as Hungary’s support for Serbia (and Republika Srpska in BiH) or the non-recognition of Kosovo by five member states (Cyprus, Greece, Romania, Slovakia and Spain) – certainly complicate any unified engagement. This incoherence is keenly felt, not least in BiH, as EUFOR’s effectiveness is challenged by a lack of a consistent political line from Brussels. Another challenge is geopolitical competition, marked by the re-emergence of rivalry between great powers—particularly as Russia and China now assert themselves in a region where both have been conspicuously absent in the recent past. This has negatively impacted EU efforts to bring the region fully within its orbit. China’s enormous infrastructure investments throughout the region often come without strings attached, thereby making EU conditionality even less appealing.

Will the EU prevail?

For Brussels to assert its credibility and authority in the region, it should move past simply engaging in crisis management and implement a more ambitious and fully integrated approach to its accession project. It should do so by reinvigorating enlargement since the promise of EU membership still represents the most powerful tool in the EU’s hands. Fast-tracking the accession process – for NATO countries such as North Macedonia and Montenegro – would clearly show that reforms are indeed rewarded. This would also reinvigorate wider grassroots support for the EU project elsewhere and dilute the nationalist narrative prevalent in various parts of the region. A unified and coherent EU stance is essential, requiring not only consistent messaging but also credible, impactful diplomatic engagement to give that voice real influence.

While the EU’s much-criticised defence and security policy in the Western Balkans may have achieved a measure of success in maintaining peace, its ultimate effectiveness is being undone by continued internal divisions and greater external competition. The EU toolbox for meaningful effects already exists, but the EU is too hesitant and too disjointed to use its available instruments to the fullest.

 

With the war raging in Ukraine and renewed volatility looming large on the European continent as a result, the EU can do one of two things. It can reinvigorate its commitment and pledges to the countries of the Western Balkans and back this up with real timelines, serious resources and grant membership to those who have made sufficient progress – or, in the shadow of Ukraine’s very real life and death struggle, the EU can surrender what influence it once had to other global players. In this contested and complex periphery of Europe, procrastination now poses the greatest threat of all.

Lincoln Gardner

[1] SFOR (Stabilisation Force) was a NATO-led multinational peacekeeping force deployed to BiH in December 1996, following the Dayton Peace Agreement that ended the Bosnian War. Its mission was to deter hostilities, stabilise peace and support the implementation of the newly signed peace accord, and support the reconstruction of civil society and democratic institutions.

[2] IFOR preceded SFOR, deploying in December 1995 to implement the military aspects of the Dayton Peace Agreement. IFOR’s mandate lasted one year.

[3] The acquis communautaire refers to “the body of common EU law”: the entire collection of rights, obligations, and legal acts (treaties, regulations, directives, case law, etc.) that are binding on all EU member states. For countries seeking to accede to the EU, accepting and implementing the acquis is a key requirement.