The Pentagon and defense contractors are heavily reliant on magnets and rare earth minerals mined or processed in China, which has suspended exports of the materials in an escalating trade war.

On Air Force fighter jets, magnets made of rare earth minerals that are mined or processed in China are needed to start the engines and provide emergency power.

On precision-guided ballistic missiles favored by the Army, magnets containing Chinese rare earth materials rotate the tail fins that allow missiles to home in on small or moving targets. And on new electric and battery-powered drones being adapted by Marines, rare earth magnets are irreplaceable in the compact electric motors.

China’s decision to retaliate against President Trump’s sharp increase in tariffs by ordering restrictions on the exports of a wide range of critical minerals and magnets is a warning shot across the bow of American national security, industry and defense experts said.

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