China publicly professes a foreign policy of non-interference, and Beijing's comments have led to an unequivocally negative response from Seoul, which sees them as tantamount to bullying. Beijing has indeed used its regional economic heft in the past to subtly remind its neighbors to maintain friendly ties with China and avoid actions — such as cooperating in U.S. defense architecture — that undermine those relations. China has even exploited South Korea's fragmented political field to stir up controversy in Seoul over defense relations with Washington. Beijing has also played on South Korea's traditional distrust of Japan to keep the U.S.-South Korea-Japan defense triangle in Northeast Asia off-balance. All of China's pressure, however, has been applied in a less overt and confrontational manner than its recent pressure over THAAD. Given the nature of its comments and the predictable reaction, Beijing's public stance may reflect a much deeper concern.