The conviction earlier this year of four Rwandans for genocide won praise for Belgium's law allowing its courts to try nationals of any country for crimes against humanity. But a decision to prosecute the Israeli prime minister, Mr Ariel Sharon, for war crimes has led Belgian politicians to seek changes to the 1993 law.
And it has raised questions about how the International Criminal Court - agreed in Rome three years ago and supported by the Irish people in last month's referendum - will function when it is established.
The four Rwandans, who included two nuns, were the first people to be convicted under the Belgian law, but there have been dozens of petitions to prosecute world leaders, including Iraq's President Saddam Hussein, the former Iranian President Ali Hashemi Rafsanjani and three former Khmer Rouge leaders.
The case against Mr Sharon was filed by a group of survivors from the Sabra and Shatilla camps in Lebanon, where at least 800 people were murdered in 1982. The murders were committed by "Christian" Phalange militias while Israeli soldiers looked on.
Mr Sharon was Israel's defence minister at the time and an Israeli investigation the following year concluded that, although he was not directly responsible for the massacre, he bore "political" responsibility.
The Belgian embassy in Tel Aviv was attacked with stones following the decision to prosecute Mr Sharon, who suggested that Belgian prosecutors would be better employed investigating their own country's atrocities in the Congo. Belgium's ambassador to Israel, Mr Wilfred Geens, attempted to reassure Israelis that his government was not acting against their prime minister.
"This perception is completely wrong. It is Lebanese citizens using a Belgian law to try to get damage reparations for their suffering in the Sabra and Shatilla massacre," he said.
But the ambassador admitted the law was making life difficult for Belgian diplomats, particularly in view of the fact that Belgium currently occupies the EU's six-month, rotating presidency. Mr Sharon's prosecution comes at an especially delicate moment for EU foreign policy chiefs, who have been hoping to enhance their role in the search for peace in the Middle East.
Belgian politicians want to change the 1993 law so that ministers in foreign governments could not be prosecuted until they leave office. But critics of the law argue that the decision to prosecute Mr Sharon highlights inadequate safeguards in the rules governing the International Criminal Court.
When 83 UN member-states agreed in 1998 to set up the International Criminal Court, they accepted it was important to avoid unwarranted or politically motivated prosecutions. They decided the court would not act if the case had already been investigated in a state which has jurisdiction over it and decided not to prosecute, "unless the decision resulted from the unwillingness or inability of the state genuinely to prosecute".
Most international opinion agrees that Israel's judiciary is independent and free of corruption, but the Belgian prosecutor decided that the 1983 investigation into Mr Sharon by a panel of senior judges was irrelevant. That investigation concluded Mr Sharon should have foreseen that the militias might murder refugees in the Lebanese camps and should have prevented the massacre. But it ruled that he was not criminally responsible for the murders.
Belgium's investigating magistrate, Mr Patrick Collignon, will conduct his own inquiry into the massacres to determine whether to charge Mr Sharon. But Israeli critics complain the case is clearly politically motivated and they point out that the claimants have not sought to pursue Mr Elie Hobeika, a former militia leader who allegedly ordered the killings.
Mr Hobeika, who is now a businessman in Beirut, says he is ready to submit to the Belgian inquiry and claims he can prove his innocence.
In fact, even if Belgium's politicians fail to push through changes to the law, Mr Sharon is unlikely to be charged for a long time. Belgium has only three investigators to handle hundreds of cases that have been taken under the 1993 law - besides dealing with other criminal investigations.
If Mr Sharon is wise to avoid visiting Belgium for the foreseeable future, the Palestinian leader, Mr Yasser Arafat, would be well advised to do likewise. Mr Haim Asulin is suing Mr Arafat for $1 billion for an attack by Palestinian paramilitaries on a school in the Israeli town of Ma'alot in 1974 that killed 20 people.
The publicity surrounding the case against Mr Sharon is likely to provoke numerous prosecutions against other leaders. It could be up to 10 years before the International Criminal Court is up and running. In the meantime, Belgium's unique law of universal jurisdiction offers hope to victims of oppression throughout the world.
If the system can avoid getting bogged down in trivial and politically motivated cases, it could provide a valuable model for how to ensure that despots find no hiding place.
