As Beijing weaponizes its dominance over rare earths supplies, US President Donald Trump is cutting deals to try to break the stranglehold. But his claim that America will have an abundance of the critical minerals in just one year’s time may be a fantasy.

The trade truce between Washington and Beijing may be holding for now, but China is increasingly wary about what’s happening elsewhere: US efforts to forge deals that could isolate Chinese firms from global supply chains. Ahead of a July 9 deadline, US ...