Rare Earths are incredibly common and could be mined in the US. The hard part is not the resources themselves but the processing and refinement of the resources, which China has invested decades into building and mastering.

If anyone is interested, our own @SeventyTwoTrillion@hexbear.net wrote an excellent essay/effort post about this whole situation a while back. It's a great read for those wanting more details about what RE minerals even really are and what the geopolitical situation is with them, at least as of a couple years ago.

The Epic Tale of How China Took Over The Rare Earth Elements Industry - An Essay