As the trial of former Yugoslav dictator Slobodan Milosevic gets underway, Nick Morrison looks at the most important test for international law since the Nuremberg tribunal.

BREAKING his impassive mask only to cast the occasional contemptuous glance around the courtroom, or nod at his supporters in the gallery, the prisoner in case number IT0245T remained silent even as he listened to the litany of horrific crimes of which he stands accused. Any one of the 66 charges levelled against former Yugoslav president Slobodan Milosevic carries a term of life imprisonment on conviction, but still the toppled dictator maintained his outward calm and continued scribbling notes.

Even as he was accused of "medieval savagery", and responsible for some of the most notorious crimes of the 20th Century, including introducing the phrase "ethnic cleansing" into common use, there was no indication on Milosevic's face that his is the most important international trial since the Nuremberg tribunal, when former Nazis were arraigned for war crimes.

And the trial, which began in The Hague yesterday, has potentially enormous implications for the future of international justice, and the international criminal court, expected to be established later this year to try crimes against humanity and war crimes.

"This trial is following on from Nuremberg, but taking it on a bit further," according to Dr Rhona Smith, senior law lecturer at Northumbria University. "The Nuremberg tribunal was set up to try certain people, and it was the first time a court had looked at individual responsibility under international law.

"Now, this is being extended, in so far as all manner of people could now be indicted and brought to trial, and effectively removing the immunity of a head of state."

The tribunal which is trying Milosevic was set up by the United Nations Security Council in 1993, in response to the stories of brutality arising from the Bosnian war, and was later widened to include alleged atrocities committed in both Croatia and Kosovo. Although the former dictator is not the first defendant to come before the tribunal, and others have been convicted, he is by far its most high profile, and the first head of state to face such charges.

"There are some precedents for the kind of actions being brought before the tribunal, which are partly under violations of the laws of war and partly under crimes against humanity," says Dr Smith. "There has been a general presumption that heads of state are immune from prosecution, but the reason this didn't apply is that the Nuremberg trials allowed the principle of individual violations of human rights, which was the first time that ever came up in international law.

"Before that, violations of human rights were purely within the remit of the state, so, in order to bring a prosecution, it would usually be one country bringing an action against another country. It was after the atrocities in Rwanda and Yugoslavia that the United Nations decided to set up tribunals in order to try people for breaches of international law."

One of the prime reasons for creating the tribunal for Yugoslavia, was the hope that it would help restore peace to the region, according to Professor Colin Warbrick, professor of law at Durham University. Although many of the alleged atrocities were carried out in the name of establishing a Greater Serbia, dominating the former Yugoslav republic, Milosevic's main aim may have been more to cling to power than any nationalistic fervour. But this does not exempt him from responsibility.

"The prosecutor has got to show that, not so much that Milosevic gave orders that genocide be committed, but that he associated himself with people who he knew would commit genocide if they had to," says Prof Warbrick. "It was not a conspiracy, so much as a joint enterprise.

"This means there isn't the difficulty of demonstrating his personal genocidal intent. There is always the difficulty that, for people at the top of the tree, you don't have the direct evidence that they killed someone or dropped bombs. But it is a question of planning, ordering or inciting, and this has often got to be proved by paper trails and developing conclusions from circumstantial evidence."

While the charges relating to all three conflicts cover allegations of war crimes and crimes against humanity, it is only over the Bosnian war that the allegation of genocide arises, the murder of thousands of Muslims in Srebrenica in 1995.

"His responsibility is alleged to be twofold," says Prof Warbrick. "In some of the cases, it is that he was directly responsible, particularly for Kosovo - that he gave the orders for these things to be done and knew they would be carried out.

"In relation to all three conflicts, there is the argument that, knowing there were violations of the laws of war, he did nothing to stop them or punish the perpetrators. I'm sure that the prosecutor will want a 'direct order' conviction against him."

Milosevic himself has consistently refused to recognise the court's legitimacy, and claims it was set up under pressure from Nato in an attempt to make Serbia responsible for what went on in the former Yugoslavia. His approach has been to say that Serbia was acting in self-defence, that the allegations of atrocities are not true, and that, if they are true, they are not attributable to him.

If chief prosecutor Carla Del Ponte fails to secure a conviction, it will be a serious blow, according to Prof Warbrick. And not only does she want a conviction, but it is also important for future international trials that Milosevic is seen to be dealt with fairly.

And the success or otherwise of the trial could have an impact on the international criminal court, which will come into existence when it has been ratified by 60 states. So far, more than 50 have signed up. The international court will have jurisdiction only over alleged crimes against humanity and war crimes, and it will cover only those states which have signed up.

Prof Warbrick says: "My view is that the most likely result is it will encourage national trials and will be something of a bar to widespread amnesties. States will be encouraged to deal with cases themselves, rather than send them to The Hague."

But, while an attempt to bring alleged war criminals to justice may be motivated partly by a desire for revenge, there is also an intention to stop such offences being committed in the first place.

"The real test is whether it deters bad conduct. The people at the top, who embark on these sorts of plans, are unlikely to be deterred by the prospect of a trial - they are either committed to their aim or they don't contemplate the possibility of defeat and capture," says Prof Warbrick.

"But the lower level people might feel it is a reason to be careful. The Yugoslav tribunal has tried a variety of defendants, and has shown it is not just the big people, but people further down the scale, who can be convicted."

And the conduct of the Milosevic trial will set a precedent for any future trials, including attempts to bring people such as Osama bin Laden to justice.

"This is a major event in international criminal law terms, and what they have to do is see if they can pull off a fair trial," says Prof Warbrick. "It is not just whether they can convict him - all sorts of lessons will be learned that will be useful for the international criminal court from this trial."