The Trump administration has moved to lock down supply by launching a $12-billion strategic stockpile of critical minerals, a direct bid to cut U.S. reliance on China for materials that sit at the heart of defense systems, power grids, and advanced manufacturing, Bloomberg reported on Monday. Rather than leaning on tariffs, permitting tweaks, or future supply promises, Washington is choosing to buy and hold the minerals outright. The stockpile will focus on rare earth elements alongside lithium, cobalt, nickel, and graphite. These materials…