They <i>did</i> try invading Soviet territory, but got slapped so badly by Zhukov that they gave up. Permenantly; the Soviets were able to send all of their military forces west when their spy in Japan confirmed that the latter had no plans to attack them.<p>Some important Japanese politicians did anything they could to stop war with the USA (Mamoru Shigemitsu, a pacifist, and Fumimaro Konoye, who considered an attack on the USA to be a very bad idea) but the militarists had the ear of the emperor, and kool aid was drunk.