The Diet has endorsed an international treaty to ban the use, development, production, procurement, stockpiling and transfer of cluster bombs. The Upper House unanimously voted to do so Wednesday. The Diet deserves praise for paving the way for Japan to approve at a fairly early date the Convention on Cluster Munitions, which Japan signed in Oslo in December 2008, together with some 90 other countries.

Credit should go to former Prime Minister Yasuo Fukuda, who in May 2008 made a last-minute decision that Japan should join the treaty despite opposition from the Self-Defense Forces. So far, eight countries have submitted an instrument of ratification to the United Nations. The treaty goes into effect six months after 30 countries have ratified it.

Civilians can fall victim to cluster bombs long after a military conflict is over. Clustered bomblets that fail to explode after being dropped from the air or launched from the ground can still explode years later. Because of their color and size, unexploded bomblets are often mistaken for toys and children become the victims.