As to the debt: that is leverage for "war by other means" ...
I've feared for a long time that all the Chinese needed to do was tell Washington that - if we didn't go along with what they wanted - they'd start selling their USA debt at pennies on the dollar. Net result, the US would be unable to borrow to support our deficit addiction and the USA would be forced into bankruptcy...
For all their faults, the Chinese are not dumb...