Can this gloomy man save Yugoslavia?

'Kostunica is a very serious man. Solid. Principled, too. But hardly a bundle of fun. Nor is he a great believerin the politics of the street'

Vojislav Kostunica is one of the gloomiest men I know. This may be an advantage for a new president of whatever remains of Yugoslavia, if that is how he emerges from yesterday's heady scenes of revolution. A "new" Federal Republic of Yugoslavia will have a ruined economy, like Romania after 1989; a burden of guilt, like Germany after 1945; ubiquitous corruption, like Russia today; and unresolved ethnic-territorial issues, like, well, old Yugoslavia.

Vojislav Kostunica is one of the gloomiest men I know. This may be an advantage for a new president of whatever remains of Yugoslavia, if that is how he emerges from yesterday's heady scenes of revolution. A "new" Federal Republic of Yugoslavia will have a ruined economy, like Romania after 1989; a burden of guilt, like Germany after 1945; ubiquitous corruption, like Russia today; and unresolved ethnic-territorial issues, like, well, old Yugoslavia.

Who is the leader upon whom such a heavy burden may fall? A large, heavy man, grey-suited, quietly spoken, painstakingly analytical, Dr Vojislav Kostunica (pronounced Kosh-TOON-it-sa) talks more like an academic than a politician. Indeed, until 10 years ago, he was just that - a politically engagé constitutional lawyer and political scientist. Now 56, he has only been an active party politician since the age of 45, when non-communist party politics became possible in Yugoslavia in 1989.

The first time we met, in 1996-97 at the time of the last great anti-Milosevic demonstrations, he took me to an old-fashioned restaurant in central Belgrade and told me that he really believed in Yugoslavia. The original Yugoslavia, that is; the Serb-dominated unitary kingdom between the two world wars (his father was an officer in its royal army). It was, he said, or at least it should have been, an exercise in British-style nation-building under a constitutional monarchy. Look how the king had given his first son a Serb name, his second a Croatian one, and his third a Slovenian - rather as British monarchs deliberately call their heir the Prince of Wales.

Most of the other nationalities of former Yugoslavia would find that a very rose-tinted view. But no, he didn't believe in the restoration of the monarchy. Apart from anything else, he said, the pretender to the throne, Crown Prince Alexander, barely spoke Serbian. When they met, they had to talk in English - which Dr Kostunica speaks fluently. Now he believed in the need for "asymmetric federalism", as a solution for Kosovo, Montenegro and Vojvodina, and perhaps also for the Serb republic in Bosnia. And he explained to me at length about his plans for the " regionalisation" of Yugoslavia. At rather boring length, I must say. Vojislav Kostunica is a very serious man.

Solid. Consistent. Knowledgeable and capable of sophisticated rational argument. Principled, too. But hardly a bundle of fun. Short on charisma. Nor is he a great believer in the politics of the street. That time, he told me how he saw unhappy echoes of 1968 in the street demonstrators' cult of spontaneity, their belief in "the movement" as an end in itself. This is the man whose future, and with it the future of all south-eastern Europe, now depends on his ability to lead and channel a movement of mass protest and civil disobedience.

In late 1998, we talked in the office of his tiny party, the Democratic Party of Serbia. His spartan offices seemed virtually empty, as if a removals van was about to arrive. Under the harsh neon light, the talk was all of Kosovo, and how its future inside Serbia must be secured by constitutional, peaceful means. Ordinary, decent Serbians would be dismayed at what Milosevic was doing there, he said. In an election held under international supervision, Milosevic could be defeated. Fat chance, I thought.

A year later, after the war and the Nato bombing, which he criticised fiercely, the office seemed even more spartan and bare. Other opposition politicians clearly had plenty of money from somewhere - and Belgrade gossip would soon tell you from where - but not Serbia's Dr K. This time, he was furious with the United States, and with Britain. "Blair! Cook!" - he spat out the names with contempt. But, he went on, "I know they are not the West. Fortunately there is also Simon Jenkins [The Times columnist who criticised the Kosovo war], Henry Kissinger [whom he clearly took as another war critic], Noam Chomsky and Harold Pinter!"

So, as our papers say, a "moderate nationalist"? Well, what exactly is a "moderate nationalist"? Some old Yugoslav hands, shocked by his strong support for the Bosnian and Kosovo Serbs, say he's as bad as Milosevic. Some even say he's more deeply nationalist than the post-communist, opportunist Milosevic.

This is both true and completely false. It's true he's been more seriously and consistently concerned about the fate of the Serbian nation than Milosevic. That is one of the reasons he was purged from Belgrade University in 1974. In other, happier places and times he would be a conservative, romantic patriot, of the kind frequently encountered in the British Conservative party (and they have some pretty rose-tinted views of the national past, too). In this unhappy place and time, he has said and done things he should regret: being photographed holding an automatic weapon among Kosovo Serbs, for example, although he says the weapon was thrust upon him.

But I have no doubt that he is genuinely "moderate", and what matters is his moderation. The difference between him and Milosevic is that between day and night. This is not just because Kostunica is supported by a coalition of less nationalist democrats. It's because he is himself, in his whole style and intellectual formation, profoundly committed to civilised, peaceful, constitutional means. And one lesson of Europe's terrible 20th century is that the means you embrace are quite as important as the ends. Perhaps more important.

This is a man who is passionate about the rule of law. Who believes in elections, institutions, negotiations. He's also a man who, precisely because he is a Serbian patriot - or nationalist, if you will - sees that the only future for his country lies in a return to Europe.

Whether he can become a popular leader of a successful revolution, we shall see. He made a fine beginning at last Wednesday's post-election "victory rally". Addressing his "dear, brave fellow-citizens, free people", as they stood waving banners and rattles, he said: "We are fighting for democracy, and democracy is based on truth, not on lies." One might almost be listening to Vaclav Havel in Wenceslas Square in Prague, 1989.

Then Kostunica addressed a skilful message to rank-and-file members of Milosevic's Socialist Party: "we will not act as did your leaders: we will not hound people who have opposing opinions; we will not burst into other people's houses... we will not remove the property of the people from the country."

In the nine days since then he has placed himself, with whatever feelings, firmly and defiantly at the front of a growing movement of popular protest. On Tuesday, he observed: "I don't like the word revolution. But what is happening in Serbia today is a revolution - a peaceful, non-violent, wise, civilised, democratic revolution." On Wednesday, he was again cheered to the echo by striking coal miners at the strategically vital Kolubara mines, which have emerged as an epicentre of this revolution (a comparison can be made with the role of the Gdansk shipyard in the Polish revolution of 1980 - although there it was the workers who started it, and opposition leaders from the capital then joined them, whereas here it is the other way round). "President! President!" the miners shouted. As I write, late on Thursday afternoon, a massive demonstration of popular anger has engulfed Belgrade. Demonstrators have stormed the parliament and are reportedly attacking the state radio and television building. Who knows what will have happened by the time you read this?

Certainly, the rapids that Kostunica has to negotiate over the next few days are far more treacherous than those Vaclav Havel faced in 1989. But history makes unlikely heroes, and Serbia's Dr K may yet be one.

The author's eyewitness accounts of the revolutions of 1980 and 1989, 'The Polish Revolution: Solidarity and We The People', are both available in Penguin paperback