No they're not "worried about US borrowing": https://www.youtube.com/watch?v=D4a3dYt-wHY
https://www.youtube.com/watch?v=7J_5Ux9S9UY
Borrowing's been like this since Reagan. Borrowing creates money for other countries to back their currencies with, that's why the EU can't be the global reserve currency: they don't borrow ENOUGH to issue enough bonds. (All fiat currency is just debt. Cash is the original bearer bond, an IOU you can pass on.)
Other countries just don't want to put their money in donnie tariff's guilded ballroom.
