Top U.S. military commanders warned Congress that reducing America's military presence on the Korean Peninsula would weaken regional deterrence, complicate warfighting plans, and embolden adversaries including North Korea, China and Russia. Testifying before the Senate Armed Services Committee on April 10, Gen. Xavier Brunson, the senior U.S. commander in South Korea, said a drawdown would be “problematic” and would undermine the strategic value of forces long positioned to impose costs on regional adversaries and to uphold security in one of...