Kim Jong Un Has a New Enemy No. 1-and It Isn't the U.S.

SEOUL—North Korean leader Kim Jong Un said the country would rewrite its constitution to label South Korea as its principal enemy, opening a new and perilous chapter as tensions rise between the two countries. The change would break with decades of North Korean doctrine, under Kim's father and grandfather, that sought to unify with the South through peaceful means, even while signaling a readiness for war. Pyongyang's policy pivot thrusts inter-Korean ties into unfamiliar territory as militarization accelerates across the region. North Korea has drawn closer to Russia, supplying its war effort in Ukraine, and revived trade with China. South…