Philippe Sands: Justice was served by the Milosevic trial

The trial has caused a vast amount of new material to emerge

The international criminal trial is a relatively recent idea. After the First World War, the Treaty of Versailles provided for the indictment of Kaiser Wilhelm II of Germany, although he was never tried after he took refuge in Holland. After the Second World War, President Roosevelt overrode Winston Churchill's proposal to execute German war criminals and Nazi leaders, and persuaded the British government to accept the principle of an international military tribunal to try the most senior Nazi officials.

The 1950s saw the first efforts to create a permanent international criminal court, but these did not come to fruition until 1998, with agreement on the Rome Statute of the International Criminal Court. The ICC itself would most likely not have emerged but for the decision of the UN Security Council to create international criminal tribunals for Yugoslavia (in 1993) and Rwanda (in 1994).

Not everyone shares the assumption that the criminal law dispensed through courts is a proper way of dealing with the most serious international crimes: the Bush administration prefers to put its efforts to deal with al-Qa'ida into the paradigm of war. We cannot have illusions about the effectiveness of internationalising the criminal law. It will not be a panacea for all the ills of the world. It will not eradicate gross violations of fundamental human rights. But it may be the least bad option for dealing with the gravest crimes, or at least some of them.

The other options are not especially attractive, or always workable. One option is extrajudicial summary justice, executing the perpetrators, but that is plainly illegal and it has few supporters. International crimes can be ignored, as they were until the second half of the 20th century. Or they can be dealt with by national amnesties, as happened in Chile, with the result that many victims were left aggrieved and feeling that justice had not been done, that there had been no "closure". Or they can be addressed through processes of "truth and reconciliation", as happened in South Africa after the end of the apartheid regime. Or they can be the subject of diplomatic deals between governments.

These options are not mutually exclusive. Since the 1940s, the international community has decided that the perpetrators of the gravest crimes should be tried before courts of law, so that their actions are criminalised. The arguments in favour include deterrence, punishment and "seeking the truth". In some cases, domestic justice is the preferred option, as in Saddam Hussein's trial (although it is widely known that the US has been actively involved). In others, the proceedings are internationalised (local courts with international judges or prosecutors), as in Sierra Leone and Kosovo. And the final option - to which Milosevic was subjected - is the fully international procedure.

These are early days for international criminal justice. The Milosevic trial will be remembered as a proceeding in which delay led to justice being denied. But that would not be right. The trial has caused a vast amount of new material to emerge into the public domain. Other trials at the Yugoslav criminal tribunal have delivered justice in a timely fashion. And other courts - national and international - may in due course deliver their verdicts on the facts that occurred under Mr Milosevic's watch. Right now the International Court of Justice in The Hague is hearing the case brought by Bosnia against the rump of the former Yugoslavia, alleging a genocide on some of the same facts raised in the Milosevic case.

It would have been preferable for the Milosevic trial to have been brought through to a judgment on his individual responsibility, whatever the outcome. But that was not the only function of his proceedings, which need to be seen in the broader context of long-term efforts to ensure that those most responsible for international crimes are not immunised from justice.

Philippe Sands QC is professor of law at University College London. His book Lawless World was published in paperback last month by Penguin