The British armed forces clung to their cluster bombs like a baby to its rattle, and some suspected that they were trying to sabotage the treaty on behalf of their American friends. But Prime Minister Gordon Brown overruled them, in the end, and Britain was among the hundred countries that agreed to a treaty banning cluster bombs in Dublin on Friday.

Well, it doesn't actually ban all cluster bombs; just current designs that leave large areas littered with unexploded bomblets that go on killing civilians for years. Israel dropped some 4 million bomblets on Lebanon during the last three days of the 2006 war, for example, and more than 30 people have been killed by them since the war ended.

If someone designed a cluster bomb whose bomblets all exploded reliably on impact, or at least within 48 hours of landing, then it would presumably be legal since it mostly killed soldiers. The major producers of cluster bombs — the United States, Russia, Israel, China, India and Pakistan — were not even at the Dublin conference, and have no intention of signing the treaty. But it's a start.