New Delhi, July 19 -- TOKYO - Japan's Defense Minister Shinjiro Koizumi called Sunday for an open national debate on nuclear weapons, saying the country "cannot avoid touching" a subject that successive governments have treated as politically untouchable for eight decades since Hiroshima and Nagasaki.

Koizumi, the son of former Prime Minister Junichiro Koizumi, stopped short of endorsing nuclear acquisition or hosting but insisted that ruling out discussion was no longer viable for a country living in an increasingly armed neighborhood. He pointed to Finland and France as evidence that other nations were revisiting deterrence assumptions that had seemed fixed for a generation.

"When neighboring countries are actively strengthening their...