The tariffs hit China WAY harder than China selling U.S. treasuries would hurt the U.S. Even if that happens, we could see a new currency or a gold standard or maybe even enough buying pressure from elsewhere to sap up. What's CHINA going to do?
THEY CAN'T DO ANYTHING. They don't have cheap labor anymore. Now they have VERY expensive labor. Cost-prohibitive labor for a lot of industries who export to the largest consumer nation. That's a deathknell for China.