The big question now that Radovan Karadzic has appeared in the dock at the Hague is whether justice will be seen to be done better than in the convoluted, inconclusive trial of the former Serbian president Slobodan Milosevic.

His trial should surely benefit from lessons learnt from those proceedings, when, quite disastrously, prosecutors "threw the book" at the defendant and the judges insisted that all charges against him over the three wars he waged – in Croatia, Bosnia and Kosovo – should be heard together.

The prosecution case alone took over three years and produced 46,639 pages of transcript, 2,256 separate legal motions (producing a further 63,775 pages), with a further 1.2 million pages of relevant disclosed documents. In this case the prosecution should concentrate on specimen counts – those for which it has the best evidence – related to the shelling of Sarajevo and to the holocaust at Srebrenica.

International prosecutors tend to overload their indictments because they think they owe a duty to victims to charge a political leader with all the criminal consequences of his policies. But trials are not truth commissions. They are adversarial proceedings to determine responsibility for particular crimes, and not a means for retrospectively testing the morality of a failed political policy. There is no point in taking five years to prove multiple counts of genocide when a defendant can be sentenced to life imprisonment on a charge that can be established in months.

The most difficult dilemma is how to give a fair trial to a man who wants to be tried unfairly. Karadzic has already announced that, like Milosevic, he will defend himself, denouncing the court and exploiting his trial to make political speeches. The adversarial system depends upon cooperation from defendants – usually by employing counsel. It cannot function effectively when the accused refuses to do anything other than disrupt and denounce proceedings.

The Milosevic judges made the mistake of bending over backwards to help the accused by appointing three amici counsel to take every point in his favour that they could.

Karadzic must not be accorded this indulgence. If he chooses to defend himself and engages with the charges there can be no objection to the court appointing a barrister to take legal points in his favour. But if he decides to ignore the case against him and to disrupt the proceedings, then adversarial trial – which tests for truth by way of open cross-examination of witnesses – simply cannot work.

In this event it may be necessary to abandon the Anglo-American model of adversarial trial and shift instead to the European inquisitorial process, in which an investigative judge examines the evidence and then presents his findings to the court, at which point the defence is entitled to challenge them. Although this procedure seems bureaucratic, the inquisitorial system is used throughout Europe (including the Balkans).

Radovan Karadzic is fit to stand trial. He is no brain-damaged Pinochet, or cancer-ridden Honecker, or weak-hearted Milosevic. The trial should begin next year – time for the prosecution to update and slim down the charges, for the accused to prepare his defence and (hopefully) for Serbia to deliver up General Mladic as his co-defendant. The trial will be as fair as Karadzic allows it to be, but if he persists in his intention to disrupt it then the gravity of the charges will require a procedure that will prevent him from turning the dock into a soapbox.

The writer is the author of Crimes Against Humanity: The Struggle for Global Justice