Fighter jets assigned to United States Forces Korea (USFK) recently conducted large-scale air drills over the high seas west of the Korean Peninsula, flying close to China’s Air Defense Identification Zone. Chinese aircraft scrambled in response, and for a fraught stretch of time U.S. and Chinese warplanes confronted one another over waters adjacent to the peninsula. At roughly the same time, U.S. strategic bombers and Japanese fighter jets carried out joint exercises in the East China Sea. These parallel maneuvers were not routine training events. They were a stark reminder that South Korea is fast becoming a frontier in the intensifying U.S.-China strategic rivalry. What is most alarming is not simply the scale or location of the drills, but the presumption behind them. Washington reportedly notified Seoul that exercises would occur, yet did not provide detailed explanations of their scope, objectives or proximity to sensitive airspace. From South Korea’s standpoint, this is more than a procedural lapse. It suggests a troubling underestimation of an ally’s sovereignty — and