WASHINGTON—The Chinese communist regime has recently signaled that it could leverage its dominance in rare earth minerals, raising alarm bells in the United States. The threat has prompted the Biden administration to take action to reduce U.S. reliance on China for rare earth metals that are used in everything from smartphones to electric vehicles to fighter jets. In 1992, Chinese leader Deng Xiaoping predicted the importance of rare earths to China’s future when he famously said, “The Middle East has oil. China has rare earths.” Today, China is the dominant global supplier of rare earths, a group of 17 chemical elements used in the production of critical components of key technologies, which could easily be used as a weapon against other countries in a trade war or a conflict. Beijing has already demonstrated that it could use rare earth elements as a retaliatory tactic. In 2010, China abruptly cut off exports of these elements to Japan during a …