New Delhi, Aug. 5 -- SEOUL - Eighty years of enforced military restraint compressed into a single cruise missile launch. When Japan's Maritime Self-Defense Force fired a US-made Tomahawk from the Aegis destroyer Chokai in the Pacific Ocean last week, it did more than test a weapon. It announced the formal end of the postwar doctrine that had barred Japan from possessing offensive strike capabilities since 1945. The missile traveled more than 1,000 miles before reaching its target. The political distance it covered was considerably farther.

North Korea's Kim Yo Jong responded with the language her government reserves for events it considers genuinely threatening. In a statement distributed by the Korean Central News Agency on Tuesday and ...