[latrare]

China has been maintaining a majority share of production for at least a decade at this point. I would wager that while that your proposed response is short as a phrase, actually getting production to match the currently relied-upon volume without China would take years, and I don't think stockpiles would last that long.

[onepointsixC]

The US accounts for a small part of the global REM consumption. Even with their majority share, unless China is willing to burn the rest of the world, the US would be able to make do. And that's not even getting into transhipping which was used to circumvent previous REM export bans.