Japan’s long-dormant defense industry is finally waking up. Constrained by a constitution imposed by the Allied military occupation after World War II, Japan has for decades adhered to a pacifist security policy. It technically maintains no military (although its Self-Defense Forces are more formidable than many foreign militaries), and until last month, the government had forbidden the export of lethal weaponry. Cultural attitudes have reinforced Japan’s pacifism: Japanese citizens have historically derided hawkish politicians and defense firms as “merchants of death.” These constraints on defense production have taken their toll. Japan is almost entirely dependent on the United States as a guarantor of its security and as a provider of military equipment. Japan’s defense industry is sclerotic and uncompetitive, in part, because the cash-strapped Self-Defense Forces had been its only customer.…