Hello. This could be a stunt performed by Trump, as he does.
Apparently, the US debt to China is astronomical. Trump wouldn't do anything to upset China, would he...?
'What Happens If China Called in Its Debt Holdings
China would not call in its debt all at once. If it did, the demand for the dollar would plummet. This dollar collapse would disrupt international markets even more than the 2008 financial crisis. China's economy would suffer along with everyone else's.' - The Balance
While I support the Hong Kong protesters I think the USA as a nation should not be involved in this issue. The private citizens and businesses of America should choose to stop purchasing Chinese goods if China is being run in a fashion they find objectionable. Government handling my trade choices for me leaves a foul taste.