We now know that states can be held responsible for genocide. We know this because the International Court of Justice said so in precisely those words in its landmark judgement this week involving Bosnia and Serbia.

The first country accused the second of planning and commanding genocide during the war in Bosnia in the early 1990s, a conflict that killed at least 100,000 people. But we also know that to prove genocide by a state is a daunting task. The ICJ also made that clear when it ruled the Serbian state did not have effective control over at least some of the forces it had unleashed.

What we also learned from this episode is that international law is a growth business, alive and well and living in The Hague, the capital of The Netherlands. There are now no fewer than three international tribunals working there.

The most recent is the International Criminal Court, under the presidency of Canadian Philippe Kirsch. It officially came into existence in 2002 when 60 nations ratified the treaty creating it. Now it has jumped into the middle of one of the world's nastiest and most brutal crises, that of Darfur in the Sudan.

The prosecutor of the ICC has sought summons for two high-profile suspects in the killings in Darfur. The first is Ali Kushayb, a leader of the Janjaweed militia, and the second is Ahmed Muhammed Haroun, the state minister for humanitarian affairs of the Sudanese government.

Both are important figures in the region and the prosecutor is accusing them of being involved in 51 war crimes and crimes against humanity, including persecution, rape, torture and mass murder.

Guilty or not

The United States has used the word 'genocide' when it has spoken of the events in the Darfur region of western Sudan. More than two million people, mostly land-tilling tribesmen and women, have fled their homes during the four-year conflict. More than 200,000 have been killed.

The ICC prosecutor alleges that the minister directed the Arab militia leader to carry out attacks that "did not target any rebel presence. Rather they targeted civilian residents on the rationale that they were supporters of the rebel forces."

The prosecutor also noted that the Janjaweed was directly financed out of Sudanese government money, and that these funds were controlled by Haroun and never audited.

Meanwhile, at the International Court of Justice, which was set up to adjudicate cases between countries, genocide has been the preoccupying issue for almost a year.

Bosnia brought the case to the court 13 years ago, in the midst of the war then tearing Yugoslavia apart, but it took a dozen years to overcome the legal hurdles raised by Serbia and Bosnian Serbs before it reached the 15 judges at the trial stage in 2006.

The judgement, in the end, was worthy of Solomon. By a majority of 13 to 2 the judges said that Serbia was not guilty of genocide or conspiracy to commit genocide. Yet the judges also ruled that the killing of almost 8,000 Muslim men and boys at Srebrenica in July 1995 by Bosnian Serb troops was an act of genocide and that Serbia "could and should have acted to prevent the genocide, but did not."

In the next breath they demanded that Serbia turn over Ratko Mladic, the Bosnian Serb general in charge of the killing at Srebrenica and now believed to be in hiding in Serbia.

Not my treaty

So carefully balanced was this decision that European commentators are divided as to whether it shows the advancing strength of international law or its limits.

Perhaps the answer to that question lies in how both Serbia and Sudan have reacted to being in the dock.

For years Serbia contested the right of the ICJ even to hear the case. This was based on the somewhat arcane defence that Yugoslavia had been suspended from the UN in 1992 at the outset of the Bosnian war. The court, as an emanation of the UN, therefore didn't have jurisdiction over Serbia, it argued, as it was the successor state to Yugoslavia.

In the end the court simply asserted its jurisdiction but there was no guarantee that, had it found Serbia guilty and imposed a massive fine, the country would have accepted the verdict.

Sudan is even more blunt in its rejection of outside authority: "The International Criminal Court has no authority to pass judgement on Sudanese citizens," said the country's justice minister, who noted Sudan never signed the treaty setting up the ICC.

In refusing to recognize the ICC, Sudan can rely on the precedent created by the very country that called its activities in Darfur genocidal, the United States. The George W. Bush administration has made it clear it will not ratify the ICC treaty, even going so far as to denounce a move in that direction by the previous Bill Clinton administration.

Washington's precedent

The U.S. is bound by treaty to recognize the International Court of Justice; it is imbedded in the UN charter which the U.S. helped draft. But its reaction to decisions it doesn't like is instructive.

In 1986 the ICJ found the U.S. guilty of "unlawful use of force" against Nicaragua. At the time, Washington was helping the opposition Contras in their war against the left-wing Sandinista government. The government of President Ronald Reagan simply ignored the verdict and refused to pay the fine.

Washington's UN ambassador was Jeanne Kirkpatrick. She summed up the American attitude this way: "This is a semi-legal, semi-juridical, semi-political body which nations sometimes accept and sometimes don't." It was, to say the least, an innovative interpretation of the responsibilities flowing from a binding treaty.

Put in more down-to-earth language, the U.S. reaction was: It's our ball and we'll only play if we're winning.

It's hardly surprising that smaller players, like Sudan and Serbia, copy the biggest boy on the field. It may not be their ball but they can try to boycott the game.