China dominates parts of the supply chain for rare earth elements and other critical materials that show up across munitions, aircraft, satellites, sensors, and night vision–type equipment (materials → components → systems). The GAO summarizes this as a major risk area, noting China’s dominance in mining/processing and the U.S. having minimal processing capacity for several critical materials.

A huge practical chokepoint is NdFeB permanent magnets (and heavy-rare-earth doped magnets for high-temp performance). GAO notes China’s unique position across multiple stages including being the only country with processing capability for each stage of the NdFeB magnet supply chain (as cited in the GAO report)

(https://www.gao.gov/assets/gao-24-107176.pdf?utm_source=chatgpt.com)

This is only a snapshot there is more to that.