Bosnia-Herzegovina asked the ICJ to determine whether the state of Serbia was responsible for genocide during the 1992-95 war in Bosnia, under the terms of the 1948 UN Convention on the Prevention and Punishment of the Crime of Genocide.
To answer that question, the court examined several issues and issued rulings that established key legal precedents.
States Can Be Liable
Serbia, in its defense brief, argued that the Genocide Convention does not provide for the responsibility of states for acts of genocide.
"I think really what it suggests is that courts are not very good instruments for achieving reconciliation in international politics," one analyst said.
But on this key point, the ICJ ruled against Belgrade.
"What [the decision] says is that not only individuals can commit genocide but also states as such," says Philip Grant, the head of Track Impunity Always (TRIAL), a Swiss-based human rights organization that monitors war crimes and genocide cases around the world. "And that is the first time that an international court has said it."
"It's the first time in legal history that you have a ruling saying a state can commit genocide," Grant adds. "You knew until then that individuals could and some have already been sentenced by the ICTY, by the tribunal for Rwanda or by national tribunals, but states -- that's a new thing."
The ICJ ruled that states, in principle, can be held responsible for genocide.
It also ruled that genocide did occur in at least one instance during the Bosnian war -- at Srebrenica, when some 8,000 Muslim men and boys were massacred in 1995, at the hands of the Bosnian Serb Army (VRS).
The court also found "conclusive evidence" that numerous other killings and massacres of Muslims occurred in other parts of Bosnia.
Hard Case To Prove
But crucially, the ICJ found that these atrocities were not enough to prove the "necessary specific intent" to liquidate an entire group that is needed for a genocide conviction.
In other words, despite evidence of atrocities and ethnic cleansing in Bosnia, as well as evidence that the Bosnian Serb Army received logistical and military assistance from Belgrade, Bosnia failed to prove that Serbia's leaders at the time set out to physically liquidate Bosnia's Muslims and acted to fulfill this plan.
Unlike in World War II with regard to Europe's Jews, there was no Wannsee Conference in Belgrade to decide on the implementation of a "final solution" for Bosnia's Muslims. Or if there was, the evidence is missing.
Grant explains why the lack of a paper trail makes it uniquely difficult to prove genocide in court.
"That's always the difficulty with the word genocide," he says. "It is the crime of crimes. It's not just any kind of crime. And the word has probably been overused to qualify multiple situations. Genocide is not a question of how many people died during a certain event. It's a question of do the authors of the killings have a specific intention to destroy a group as such -- a group that is political or religious or [ethnic], etc. And that is very complicated to prove. When it's a criminal issue, you have to prove it. The burden of proof is on the prosecution; it's not on the defense. So if you don't have a paper trail, if you don't have that kind of document, it's very, very difficult to prove."
From the start, Bosnia faced an uphill battle at the ICJ and in this sense the final ruling was not a surprise, says Grant.
"The ruling, if you read it correctly, doesn't mean that genocide wasn't committed," he tells RFE/RL. "It was indeed committed. It doesn't mean that Serbia was not complicit to genocide. It just says it wasn't proven that Serbia was complicit to genocide. And that's sufficient to lose the case. But if you read between the lines, I think it's more a question of burden of proof than about what happened. Bosnia had to prove that there was from the state of Serbia, from the state apparatus -- the military, the police -- an intention to destroy or to help the Serbs from Bosnia to destroy a specific group in Srebrenica."
Had the late Slobodan Milosevic, who was Serbia's president at the time, been convicted of genocide by the international criminal tribunal at The Hague, a key link tying Belgrade to a policy of genocide in Bosnia might have been established.
Residents of Sarajevo demonstrate against the ICJ ruling on February 27 (epa)
But since Milosevic died in March 2006 with his trial incomplete, that point is now moot.
Marc Cogen, professor of international law at Belgium's Ghent University, says that the ICJ ruling reaffirms the important distinction that must be maintained between ethnic cleansing and other grave crimes and the ultimate crime -- genocide.
"[The ruling] clarifies international law in the sense that [it reaffirms that] genocide should not be taken lightly and only in serious cases, where there is a planned approach of extermination, instead of ethnic cleansing or other [intention], only in this case should the word genocide be used by the media and by the international law community," Cogen says.
The ICJ decision in no way affects the ability of other courts such as the International Criminal Tribunal for the former Yugoslavia (ICTY) or the International Criminal Court (ICC) to convict individuals for acts of genocide.
But when it comes to holding an entire state to account, things get more complicated.
The Reconciliation Process
This raises the larger issue of postconflict reconciliation.
Countries operate on two levels: government-to-government and people-to-people.
As demonstrated by Western Europe after World War II, long-lasting peace cannot be achieved merely through state treaties, reparation agreements, and other legal instruments. Divided nations have to be brought together on a more personal level.
The ICJ, which was set up to adjudicate disputes among states, may not be the proper forum for that, according to Timothy Waters, of the Indiana University Law School.
"I think really what it suggests is that courts are not very good instruments for achieving reconciliation in international politics," Waters says. "Courts have to reach decisions: is there genocide -- yes or no? They're not really good narrative history tellers and what we really need, in a sense, are common histories, common narratives, to have reconciliation."
As this week's reactions in the Balkans to the ICJ ruling demonstrated, peace may exist, but reconciliation is still a long way off.
(Irina Lagunina of RFE/RL's Russian Service and Ilirjana Bajo of RFE/RL's South Slavic and Albanian Languages Service contributed to this report)