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In the Indo-Pacific region, a new phase of undersea strategic competition is emerging. Nuclear-powered submarines, once largely confined to the arsenals of nuclear-weapon states, are increasingly being incorporated into the defense strategies of states that do not possess nuclear weapons. South Korea has transitioned from long-standing discussion to a concrete program for domestically built nuclear-powered submarines; Japan is now openly debating whether nuclear propulsion should be an option for its future submarine force; and Australia is already putting an ambitious plan into action under AUKUS.
