China can calculate the threat from 50,000 American troops in Japan, but what keeps Xi Jinping awake at night is Japan’s decision to double its defense spending and build hypersonic missiles. For 75 years, Japan’s pacifist constitution was China’s greatest strategic asset in Asia, and now Beijing is watching that advantage disappear in real time.As a military historian studying East Asian security, I see China facing a nightmare scenario they never planned for: Japanese rearmament. Xi Jinping’s aggressive behavior has triggered exactly the response Beijing most feared – awakening a military-industrial giant with the technology, geography, and historical motivation to challenge Chinese hegemony.
