Evidence of a monstrous "hate crime" -- mass extermination and "ethnic cleansing" of Bosnia's Muslims in the 1990s -- was presented last week as former Bosnian Serb leader Radovan Karadzic's genocide trial began at the International Criminal Tribunal in Holland.

Most Americans don't know the long history that turned Balkan people against each other, setting the stage for the horrible Yugoslavia war. Here's a thumbnail account:

Ten centuries ago, Europe's Christianity split between Rome and Constantinople. The fault line of the division went up through the Balkan Mountains north of Greece. Slavic peoples living west of the line became Roman Catholics; Slavs on the other side became Eastern Orthodox.

Later, marauding Turks drove northward through the Balkans to Vienna, converting many conquered villages to Islam. Thus the Balkan people, all similar South Slavs, were tribalized into three cultures: Catholic Croats and Slovenes, Muslim Bosnians and Kosovars, and Orthodox Serbs. Simmering conflicts between them grew.

During World War II, Balkan Croats and Muslims mostly sided with Hitler, fighting and persecuting Serbs. After the war, communist dictator Tito seized power over Yugoslavia. By force, he prevented strife between the three ethnic groups. But Tito died in 1980 and communist Eastern Europe began unraveling. Yugoslavia was torn apart when its old religio-ethnic tribalism no longer could be suppressed.

Serbian demagogue Slobodan Milosevic fanned tribal feelings of superiority among Orthodox Serbs. As a result, Muslim Bosnians and Kosovars, plus Catholic Croats and Slovenes, began breaking away from Yugoslavia. Milosevic led warfare against them. He was accused of "ethnic cleansing" to wipe them out and create a Greater Serbia populated only by Serbs.

Radovan Karadzic, leader of Serbs within Bosnia, attempted to prevent his region from seceding. Failing that, he armed Serb troops to massacre Muslims in Bosnia. He ordered sniper attacks on Sarajevo civilians and mass slaughter of thousands of Muslim men and boys in "safe havens" like Srebrenica.

Milosevic was tried for war crimes in 2006, but died in Holland before he could be convicted. Last week, Karadzic refused to attend his trial, but prosecutors presented ugly evidence against him -- such as phone recordings in which he vowed to turn Sarajevo into "a black cauldron where 300,000 Muslims will die. They will disappear. That people will disappear from the face of the Earth."

The evil of genocide surges periodically, always rooted in ethnic tribalism. Prosecuting a few leaders 20 years after the horror is scant justice, but it's the least that must be done.

Evidence of a monstrous "hate crime" -- mass extermination and "ethnic cleansing" of Bosnia's Muslims in the 1990s -- was presented last week as former Bosnian Serb leader Radovan Karadzic's genocide trial began at the International Criminal Tribunal in Holland.

Most Americans don't know the long history that turned Balkan people against each other, setting the stage for the horrible Yugoslavia war. Here's a thumbnail account:

Ten centuries ago, Europe's Christianity split between Rome and Constantinople. The fault line of the division went up through the Balkan Mountains north of Greece. Slavic peoples living west of the line became Roman Catholics; Slavs on the other side became Eastern Orthodox.

Later, marauding Turks drove northward through the Balkans to Vienna, converting many conquered villages to Islam. Thus the Balkan people, all similar South Slavs, were tribalized into three cultures: Catholic Croats and Slovenes, Muslim Bosnians and Kosovars, and Orthodox Serbs. Simmering conflicts between them grew.

During World War II, Balkan Croats and Muslims mostly sided with Hitler, fighting and persecuting Serbs. After the war, communist dictator Tito seized power over Yugoslavia. By force, he prevented strife between the three ethnic groups. But Tito died in 1980 and communist Eastern Europe began unraveling. Yugoslavia was torn apart when its old religio-ethnic tribalism no longer could be suppressed.

Serbian demagogue Slobodan Milosevic fanned tribal feelings of superiority among Orthodox Serbs. As a result, Muslim Bosnians and Kosovars, plus Catholic Croats and Slovenes, began breaking away from Yugoslavia. Milosevic led warfare against them. He was accused of "ethnic cleansing" to wipe them out and create a Greater Serbia populated only by Serbs.

Radovan Karadzic, leader of Serbs within Bosnia, attempted to prevent his region from seceding. Failing that, he armed Serb troops to massacre Muslims in Bosnia. He ordered sniper attacks on Sarajevo civilians and mass slaughter of thousands of Muslim men and boys in "safe havens" like Srebrenica.

Milosevic was tried for war crimes in 2006, but died in Holland before he could be convicted. Last week, Karadzic refused to attend his trial, but prosecutors presented ugly evidence against him -- such as phone recordings in which he vowed to turn Sarajevo into "a black cauldron where 300,000 Muslims will die. They will disappear. That people will disappear from the face of the Earth."

The evil of genocide surges periodically, always rooted in ethnic tribalism. Prosecuting a few leaders 20 years after the horror is scant justice, but it's the least that must be done.