SEOUL, Aug. 25 -- The United States Marine Corps notified South Korea in June. Quietly. No announcement. The Ssangyong exercises - the biennial amphibious landing drills that rehearse exactly the kind of combined military assault that defence of the Korean Peninsula would require - would not happen this September. The reason given was blunt: American forces were constrained. The Iran war had consumed them.

South Korea held the news for weeks before a Marine Corps spokesperson confirmed the cancellation publicly. "The US Marine Corps formally notified our forces in June that its ability to deploy forces during this year's Ssangyong exercise would be constrained due to the situation in the Middle East," the spokesperson said. Seoul and Was...