China, Myanmar and now Darfur ... the horror of genocide is here again | Simon Tisdall

Each time it happens, the world insists: never again'. But the political and moral blindspots that allow these atrocities will persist until the lessons of history are learned

It's happening again. In Darfur, scene of a genocide that killed 300,000 people and displaced millions 20 years ago, armed militias are on the rampage once more. Now, as then, they are targeting ethnic African tribes, murdering, raping and stealing with impunity. They" are nomadic, ethnic Arab raiders, the much-feared devils on horseback" - except now they ride in trucks. They're called the Janjaweed. And they're back.

How is it possible such horrors can be repeated? The world condemned the 2003 slaughter. The UN and the International Criminal Court (ICC) investigated. Sudan's former president, Omar al-Bashir, was charged with genocide and crimes against humanity along with his principal allies. The trial of one suspect, known as Ali Kushayb, opened last year. Yet Bashir and the guilty men have evaded justice so far.