In 1980 the US had 33 primary aluminium smelters. It has 4 today.
Over the same period China went from ~0% of global production to 59%. The crossover happened around 2003โ05 and the gap has widened every year since.
Aluminium is in aircraft, vehicles, defence systems, construction, and packaging. The US lost 88% of its smelting capacity over 45 years โ not to a crisis, not to a war, but to incremental decisions that each made sense individually.