China will ban rare earth exports to US if US continues to bully China.

https://www.bloomberg.com/news/articles/2019-05-20/xi-s-trip-to-rare-earths-plant-stokes-talk-of-trade-retaliation

Currently, China produces more than 90% of the rare earth supply and this gives China the monopolistic power.

Rare earth materials are used in many electronic applications, batteries and military weapons.  Without rare earths, the US modern industries including defense contractors will suffer greatly.

The US will have to bow to China if China is to ban rare earth exports to the US.  It is not easy to find replacements for rare earth suppliers because the production process is highly toxic.