A junior minister in Japan's ruling government stepped down on Wednesday for saying Japan should consider abandoning a decades-old ban on nuclear weapons, dealing a blow to Prime Minister Keizo Obuchi. But Obuchi hoped that the swift handling of the incident would limit the damage at home and abroad as he prepared for an extra session of parliament to enact economic stimulus and other key legislation after reshuffling his cabinet earlier this month. Shingo Nishimura, one of two parliamentary vice ministers appointed to back up the defenceminister, tendered his resignation to Defence Minister Tsutomu Kawara.