The car bomb that nearly killed President Kiro Gligorov of Macedonia on Tuesday has sent tremors through the southern Balkans and created the most dangerous instability in the region since the breakup of Yugoslavia four years ago.
Supported by a small but symbolic UN peacekeeping force and backed by clever American diplomacy, President Gligorov had kept a balance between rival ethnic groups among his two million people and avoided potential conflicts with Albania, Serbia, Bulgaria and Greece. His disappearance from the scene - at 78, he is unlikely to recover quickly from severe head injuries - could end all that.
The greatest danger is that blame for the bombing could fall on a minority group, such as the Albanians, detonating a civil war that would draw in outside interference. Macedonia has an extreme nationalist movement capable of political violence. But Western governments have learnt that the bomb was a highly sophisticated device, believed to be beyond the capacity of local groups.
There is another possibility. The country has become a centre for the Balkan heroin trade and official corruption has been fuelled by Mafia drug money. The Italian Mafia is the only group in south-east Europe to use car bombs to assassinate its foes in recent years. And the Macedonian government was under discreet Western pressure to crack down on drugs.
But it is almost irrelevant whether President Gligorov was attacked by the Mafia or by any of the numerous extremist elements in his landlocked and impoverished country. The fact is that the bombing was a perfectly calculated act of terrorism which achieved its objective: maximum destabilisation.
The instantaneous reaction by Greece - bitterly at odds with Macedonia since its independence - was proof of the fear it unleashed.When the bomb went off, Greece and Macedonia were just beginning official talks to resolve their dispute over the former Yugoslav Republic's name and constitution. By ten minutes past six that evening, Athens had sent surgeons with specialist equipment from Thessaloniki to Skopje to join the doctors trying to save Mr Gligorov's life.
Prime Minister Andreas Papandreaou and the opposition all condemned the bombing and Athens put its forces on alert along the northern border. The Macedonians sealed off theirs and Bulgaria tightened security along its frontier with Macedonia.
This attack of the jitters should put every government involved with the former Yugoslavia on its guard. The sensible behaviour of Athens will attract firm European support and its negotiations with Macedonia will go ahead.