Those who described Russia’s military mobilisations as the gravest threat of war in Europe for more than 75 years neglected, intentionally or not, the some 100,0000 lives lost during the bloodshed that occurred during the disintegration of the former Yugoslavia in the early 1990s.

Thirty years on, it is this same area, now referred to as the Western Balkans, which remains vulnerable to contagion from the crises in eastern Europe. As Russia accelerates its invasion of Ukraine, there are mounting concerns about other challenges to a security architecture that, though imperfect, has largely stabilised a key part of Europe.

As with Ukraine, the European Union’s nonchalance towards the clear and present dangers facing the Western Balkans has served only to hack away at the previously uncontested faith in its policies that adherents to its path had almost dogmatically upheld. Bosnia-Herzegovina is facing a resurgence of secessionist tendencies, while attempts to normalise relations between Serbia and Kosovo have hit the rocks. The EU’s leverage is not what it once was, nor indeed is that of the US; the stains of the Trump years proving hard to erase.

Talk of war had already returned to the streets and cafes of Bosnia-Herzegovina even prior to the latest escalation in Ukraine. For nearly three decades, the country has been divided into two regions, run by two separate entities, the Republika Srpska, which is mainly composed of Serbs, and the Bosniak-Croat-populated Federation of Bosnia and Herzegovina. Now, the Republika Srpska has taken tangible steps to further contest Bosnia-Herzegovina’s sovereignty; threatening its withdrawal from state institutions and the establishment of parallel bodies in key domains, including the armed forces and judiciary. It is the most profound crisis facing the country since the 1995 Dayton Peace Agreement, itself imperfectly conceived and drafted, ended the war.

Though the prospects of the Republika Srpska seceding remain slim, these provocative steps are a direct challenge to the constitution of Bosnia-Herzegovina. Potential confrontations – for instance, should there be attempts to remove the country’s armed forces from the entity’s territory, as has been proposed – would create a host of security dilemmas that could further inflame tensions.

Old and unhealed wounds have been reopened. Conflict-generating rhetoric is becoming more pronounced. Bosnia’s Croats have sensed the opportunity to pursue their own interests, pushing electoral reforms designed to further benefit the ethno-nationally grounded incumbents at the expense of more civically minded alternatives. Speculation is rife that elections scheduled for this autumn could well be postponed, possibly indefinitely, further deepening the country’s political gridlock. Constitutional reform seems further away than ever.

The scope for further external manipulation is clear. Russia has vigorously opposed the new high representative, Christian Schmidt, as part of a broader campaign to close his office and bring to an end the Bonn Powers, which were used by the last high representative, Valentin Inzko, to impose changes banning the denial of genocide and other established war crimes, as well as the glorification of war crimes.

Even the mandate of the EU’s own military deployment, EUFOR, could be threatened by Russia at the UN Security Council, further weakening the visible deterrent on the ground. Any attempt by Bosnia-Herzegovina to pursue NATO membership, meanwhile, will likely be scuppered by the Republika Srpska, which enjoys various forms of Russian backing and is used by Moscow to exert profound influence over Bosnia-Herzegovina.

Meanwhile, dialogue between Serbia and Kosovo has ground to a halt in recent years. Kosovo’s own unilateral declaration of independence remains unrecognised by five EU member states, while its bid for visa-free travel in the Schengen Area has fallen upon deaf ears, despite the country fulfilling the demanding conditions set by the European Commission.

Europe has taken the lead in the process of normalising relations between Serbia and Kosovo, yet seemingly hesitates when it comes to brokering a final deal. Another window of opportunity is deemed to exist after elections in Serbia this April, though the dilution of incentives to compromise for both countries suggests that the process will remain moribund.

With its bouquet of envoys – from the US, EU, UK and now Germany – the Western Balkans is hardly short of diplomatic attention. Each of the anointed tries to bring a renewed sense of purpose and direction, only to be hamstrung by their distracted or disinterested administrations. Rhetorical flourishes are rarely underpinned by substance.

The commitment of EU member states to shared and cohesive positions has been brought into question. Enlargement has become a hollow promise, even if the Union continues to invest considerable political and financial capital in the Western Balkans. And yet there is a determination to proclaim progress and demonstrate success that works to the neglect of those intent on real and fundamental change.

On the question of possible sanctions against the Republika Srpska, there is a noticeable and disconcerting lack of consensus; spearheaded by Viktor Orban’s Hungary, but ably supported by Croatia and Slovenia. If it wasn’t clear until now, Europe’s illiberal streak compromises its pursuit of a unified and principled foreign policy.

Even where liberalism apparently reigns, self-interests trump longer-term considerations. The Union is willing to do deals, no matter how seemingly unpalatable, to fend off short-term disruptions. The refugee/migrant crisis of 2014-15 remains a case in point, with agreements put in place to ensure countries helped stem the flow of migrants into the EU while a blind eye was turned towards various violations of fundamental European freedoms and values. So long as there are no unexpected outflows from the Western Balkans, Western Europe will be happy to pick off the cream of the region’s labour.

The crisis over Ukraine threatens to occupy and overwhelm European diplomacy at the expense of the Western Balkans. This would be a grave mistake. Instead, the lesson must be that problems left unattended will fester and mutate until their contemporary manifestations cannot be restrained without considerable investments of resources and personnel, and even then only when it is too late.

Though its credibility has been undermined, the EU and its partners can continue to build resilience against malign external influences. The region has long been a hard sell for member states, but if events in Ukraine can’t bring clarity of conviction then nothing will.