the US can embargo Windows updates

That's actually a funny and real example. For a long time there was a heat map that showed where the concentration of MSIE 6 was. It was China because every copy of Windows was pirated and may have also had government keys hard coded in the pirated copies. They were locked at the patch level the pirated version was made from and it was impossible to patch it otherwise.

Either way the US has nearly unlimited amounts of rare earth material in raw form. Its just much more expensive and time consuming to process it in the US and US regulations make it even more expensive. China does not follow our environmental laws and we breath the output of that. That's why they are processed in China. Processing it in the US would reduce global pollution for a hefty price.

> China does not follow our environmental laws and we breath the output of that.

Some of it perhaps. A lot of it is more localised, going into their dust clouds and water supplies. We should face the fact that moving rare earth processing to the US would mean either expensive mitigation measures or a lot more Americans experiencing health conditions - and probably both.