To make fspeech's point more obvious, while the rare earth materials may only be worth billions to China over multiple years, they could destroy entire industries worth trillions of dollars over the world, and in particular US. This is less obvious for other China exports, but with the "leverage" that's mentioned, you can assume for each dollar worth of imports lost from China, US may lose more than one dollar, possibly several dollars worth of production. On top of alienating multiple other trade partners and sending them to work with China. The US is losing its guts, its intestines, its kidneys, while China may only be losing an arm or a leg, or even just some of muscle and blood.