Their choice of self-restraint rested on many factors, none more critical than the security afforded by military alliance with the United States, bolstered by deployment on their territory of U.S. military forces. As historian Michael Howard explained years ago, reassurance of allies is scarcely less crucial than deterrence of adversaries. Durable strategic stability depends on both. [...]
Gradually, reluctantly, Beijing has been drawn into the multilateral campaign to pressure Pyongyang economically and politically. Recent months have seen China joining strong U.N. Security Council resolutions and stern sanctions against North Korea, particularly in pledging curtailment of trade between the two neighbors. On present evidence, it remains doubtful that even the sharpest diplomatic and economic measures will dissuade Kim from his nuclear and missile ambitions.
Perhaps it is time to explore a different initiative: Could China reassure North Korea as the United States reassures South Korea? As Beijing has grown anxious over North Korea’s behavior, it has qualified its 1961 defense agreement with Pyongyang by emphasizing that it would assist against attack — but it would not support the Kim regime if it began a war. [...]
That guarantee would be most credible, however, if coupled with actual deployment of Chinese forces on North Korean territory. A symmetrical policy of reassurance could involve possibly 30,000 Chinese military personnel stationed there, a total comparable to U.S. forces south of the 38th parallel. [...]
The task of persuading North Korea would fall to the Chinese, just as the United States would have to surmount predictable South Korean apprehension regarding the concept. North Korean leadership might perceive the offer of Chinese troops less as a stabilizing arrangement than as a prelude to overthrowing the Kim regime.