Anybody with large enough holding of US treasuries has leverage over the US: Large selling of those treasures will raise the yield on them, which is the last thing the US in its current situation needs.
Of course, such selling will crash the treasuries, incurring huge losses to the seller. Still, hoping/pretending there is no leverage is closing your eyes to the reality.
Reciprocally, US has capability to screw over such large holders by inflating itself out of debt, leaving them holding worthless paper/bits.
That's why China has been carefully riding itself out of treasuries for years.