China's control over critical minerals is increasingly disrupting the U.S. defense supply chain, affecting over 80,000 weapons components reliant on Chinese-controlled inputs. Key defense manufacturers, including Lockheed Martin, report shortages in essential parts such as missile magnets, infrared sensors, and drone motors, leading to potential delays, cost increases, and risks to safety stock levels. These developments follow China's imposition of export curbs on seven rare earth elements in response to U.S. tariffs, intensifying global concerns about supply chain security in defense, energy, and electric vehicle manufacturing sectors. Analysts highlight China's decade-long strategy to reduce its own economic vulnerabilities while maintaining global dependence on its rare earth resources, creating a technological and industrial moat. The global competition to secure critical raw materials is accelerating as countries pursue net-zero emissions goals, emphasizing the importance of international cooperation in supply chains amid this geoeconomic landscape.