Nearly three decades ago, the international community left Bosnia to bleed out. Under the eyes of the western powers, who might have intervened early on and deflected an all-out humanitarian catastrophe and a genocide, the country underwent nearly four years of conflict. All wars are cruel, but the Bosnian war was a template for misery. The capital, Sarajevo, once the site of the 1984 winter Olympics and a symbol of multicultural, multi-faith communities, was subjected to a medieval siege. Its inhabitants – intellectual, cosmopolitan Europeans who enjoyed cafe society, classical music and poetry – were starved, bombed, sniped and deprived of any contact with the outside world. Hundreds of thousands of people died, many of them children. The war concluded after a genocide in the town of Srebrenica, which could have been prevented had irresponsible diplomacy and inertia not prevailed. In July 1995, nearly 8,000 Muslim men and boys were separated from the women under the eyes of UN peacekeepers who stood by and failed to defend them. They were loaded onto trucks, not knowing they were being sent to death, and then hunted down in forests or gunned down en masse in factories. Some of their bodies have never been recovered. Finally, in the wake of that tremendous sorrow, then US president Bill Clinton ordered air strikes and American diplomats arm-wrestled former the warring parties to a shaky peace agreement, the Dayton Accords. It was a cynical move on Mr Clinton's part: he waited until the last possible moment to intervene, strategically deflecting attention from his own domestic political turmoil. The Dayton Accords were never meant to last decades. They were insufficient, and in many ways, rewarded the perpetrators of that war, which included the Bosnian Serbs and their masters in Belgrade: then Serbian president Slobodan Milosevic and his cronies. There were few provisions for constructive transitional justice, and that meant most of the victims – of concentration camps, rape camps, or ethnically cleansed villages – never saw justice. Even though there were concentration camps in the heart of Europe and women were herded off to former gymnasiums and hotels and raped multiple times a day, Bosnia was still meant to heal. The post-war years were spent trying to rebuild the country, but also to provide for those who had been pushed out of their homes and villages to attempt to live in the new state of Bosnia and Herzegovina. This state now consists of two entities, Republika Srpska and the Federation of Bosnia and Herzegovina. To make it even more confusing, the latter consists of 10 separate "canons" each with their own legislatures and governments. From the beginning, those of us watching the Balkans carefully knew there would be trouble, and that the Dayton Accords that were meant to foster peace would actually foster a deepened resentment and ethnic divides. The provisions that divided the entities also carved deep ethnic and religious divisions. In cities such as Mostar – bitterly fought in the summer of 1993 when those besieged in the eastern part of the city existed on cherries from the trees and little else – the former frontlines continue to mark a boundary between Muslims and Croats. In divided Bosnia, segregated schools sprung up – essentially two schools under one roof. In Travnik – a medieval central town that witnessed heavy fighting early on in the war, and where thousands of refugees flooded for safety – children go to the same building but study two different textbooks, two different "languages". Catholic Croatian children learn Croatian; Muslim Bosniaks learn Bosnian. Pre-war, there was one language known as Serbo Croat. Last October, in Banja Luka – the capital of Republika Srpska – Milorad Dodik, the Bosnian Serb leader and ultra-nationalist, announced plans to withdraw the republic from major state institutions. He wants to set up separate tax offices, army and security apparatus. This is effectively secession. As it was secession that launched the former Yugoslavian wars back in the early 1990s – first Slovenia, then Croatia, finally Bosnia – this news sends a terrifying message to the country. So do reports that pro-Serb police are training on Mount Jahorina – a ski resort outside Sarajevo that was used as the base to shell and snipe the city – seen as provocation. The chief international representative in Bosnia, Christian Schmidt, in a report to the UN, says Bosnia is facing "its greatest existential threat of the post-war period". Are we headed for another war? "See you in 20 years," my Bosnian friends quipped in 1995 after the war ended, meaning it would all start up again. It seemed absolutely improbable then, but today, Europe is on shaky ground. There are concerns about a military standoff between Russia and Ukraine, Belarus and Poland are involved in a migrant crisis, and now Republika Srpska maybe trying to break away. Those who care about Bosnia must, therefore, act quickly to avoid another potential bloodbath. US President Joe Biden has effectively signalled that he is shifting America's focus away from so-called trouble zones (aside from Taiwan). The collapse of Afghanistan has led to a new wave of refugees, some freezing to death in forests on the Poland-Belarus border. But the US is reeling from the pandemic, racial tensions and a resurgent Republican Party ahead of the 2022 midterm election. Bosnia will be the last thing on Mr Biden's mind. And yet, Bosnia must not be abandoned again. Thirty years ago, the country died slowly because Europe and America could not agree on who should save it. This was not the case in Kosovo, in 1999, when rapid Nato-led air strikes ended the aggression. Kosovo was a guilt war – the world acted fast because of the Srebrenica genocide. Since Dayton, the "care" and long-term stability of Bosnia was largely put in the EU's hands. But the bloc has struggled, and Bosnia is a long way off from being admitted. With a vacuum like this, nationalism, hate rhetoric and ethno-political divisions are stronger than ever. In 1992, the British envoy David Owen painfully told the Bosnian people: "Don't dream dreams. The West is not going to come in and save you." His words are a harbinger of what Bosnia could become: a failed state in the centre of Europe, vulnerable to becoming a harbour for terrorist groups and traffickers, and a road for refugees on their way to "Fortress Europe". But it has also meant allowing Moscow to extend its sphere of influence and opening the door to Iran, Turkey and possibly China. The years I spent in Bosnia were amongst the most painful of my life. To see a country disintegrate before one's eyes, when it could have been saved early on, was perhaps the most vital lesson we learnt to prevent future wars. If you walk through the graveyards of Sarajevo – at one point, there were so many dead that the football pitch was turned into a cemetery – you will see the markers of young men and women born in the 1980s who died during those three-and-a-half years of siege. They did not have to die. They could be alive today. This time, the international community cannot afford to look away.