SARAJEVO (Reuters) - With row upon row of empty red chairs, one for each of the 11,541 victims of the siege of Sarajevo, Bosnia on Friday remembered when war broke out 20 years ago and the West dithered in the face of the worst atrocities in Europe since World War Two.
The anniversary finds the Balkan country deeply divided, with power shared uneasily between Serbs, Croats and Muslims in an unwieldy state ruled by ethnic quotas. It languishes behind ex-Yugoslav neighbors on the long road to the European Union.
"The victims fell here because we wanted to preserve the state, but I fear they fell in vain," said 32-year-old social worker Kanita Hulic, one of thousands gathered in central Sarajevo for a memorial concert.
Some 100,000 people died and 2 million people were forced from their homes as Bosnia gave the lexicon of war the term "ethnic cleansing". Slow-motion intervention eventually brought peace, but at the cost of ethnic segregation.
Underscoring the disunity, Bosnia's autonomous Serb Republic ignored Friday's solemn remembrance of the day shots fired on peace protesters in downtown Sarajevo marked the start of the war.
In a blood-red symbol of loss, empty chairs stretched 800 meters down the central Sarajevo street named after socialist Yugoslavia's creator and ruler for 35 years, Josip Broz Tito.
Smaller chairs represented the more than 600 children killed in the 43-month siege by Serb forces that held the hilltops. Thousands of people gathered for a concert in remembrance with a choir of 750 Sarajevo schoolchildren.
On Thursday, cellist Vedran Smailovic, who became an icon of artistic defiance when he played on a central Sarajevo street as the city was shelled, played again for the first time in his hometown since he left in 1993 as part of an exodus of thousands.
Queuing for water or shopping at the market during the siege, Sarajevans were picked off by snipers and random shelling. Running out of burial places, many of the bodies were interred beneath a hillside football pitch.
"We were moving targets with only one principle left - that we would stay in the city," said Bosnian artist Suada Kapic.
The war happened on NATO's doorstep, a few hours' drive from Vienna or across the Adriatic from Italy. Its grisly imprint survives today in the bodies still being dug up in eastern Bosnia and the million people who never returned to their homes.
Politics still runs along ethnic lines, spawning bloated networks of patronage that resist reconciliation or reform.
"Ethnic division is catastrophic for Bosnia," said retired lawyer Marko Petrovic.
"Bosnia can't survive unless we are united, based on humanity and the kind of people we are, not what our names are."
Bosnia was Yugoslavia in a bottle, a mix of mainly Orthodox Serbs, Catholic Croats and Muslim Bosniaks.
But as Yugoslavia began to fall apart, and Bosnia's Muslims and Croats voted in a referendum in favor of independence, Serb forces with the big guns of the Yugoslav army seized 70 percent of Bosnian territory, driving out non-Serbs.
The Muslims and Croats fought back, and against each other.
The United Nations sent blue-helmeted peacekeepers but gave them no mandate to shoot back. It was only after the so-called U.N. safe haven in Srebrenica fell in July 1995 to Serb forces, who then massacred 8,000 Muslim men and boys, did NATO use force, eventually bombing the Serbs to the negotiating table.
Bosnia taught the world tough lessons in humanitarian intervention that could yet be echoed in Syria, where the United Nations is probing the deployment of unarmed monitors under a peace plan to end the conflict between rebels and forces under President Bashar al-Assad.
Bosnia's U.S.-brokered peace deal silenced the guns but created a state of 120 ministers that has absorbed nine billion euros ($11.76 billion) in foreign aid.
Ethnic bickering left the country without a central government for the whole of 2011, and the Serb Republic regularly forecasts the country's disintegration if it is pushed to cede more powers to Sarajevo.
The West "can only delay it, but it will never stop it", Serb Republic President Milorad Dodik said of the possibility of collapse in an interview with the Banja Luka daily Nezavisne Novine.
"They have to understand that Serbs want the Serb Republic, and not Bosnia."
The West hopes the pull of the EU on the region and greater economic cooperation will nudge Bosnia towards a more functional form of government.
Neighboring Croatia will join the EU in July next year. Serbia, which under strongman Slobodan Milosevic conspired with Croatia to dismember Bosnia, became an official candidate for EU accession last month, in part as reward for capturing Bosnian Serb wartime commander and genocide suspect Ratko Mladic.
Bosnia is yet to apply. To do so, it must amend its Dayton-era constitution to reflect a ruling by the European Court of Human Rights that its strict system of ethnic quotas is discriminatory.
"I think the majority of the people of this country realizes that all of us came out of this war as losers, but I fear the majority has also failed to learn the lessons," said 46-year-old Radoslav Zivkovic, a Serb in the wartime Serb stronghold of Pale.
Additional reporting and writing by Matt Robinson; editing by Andrew Roche