Advanced U.S. weapons are almost entirely reliant on rare-earth materials only made in China—and they could be a casualty of the trade war. Keith Johnson and Lara Seligman write in Foreign Policy that President Donald Trump has often argued that China has much more to lose than the United States in a trade war, but critics say his administration has failed to address a major U.S. vulnerability: Beijing maintains powerful leverage over the war-making capability of its main strategic rival through its control of critical materials.