Comment by vonzepp

If India buys a widget off Brazil it will probably be paid in dollars. Therefore, people need to own dollars. Thus a demand for US debt. This lowers the potential interest rate. Other countries who's currency is not a need for people to buy, their debt is purchased by the attractiveness of its offering (i.e interest rate). If US dollar is no longer required than government bonds have to be attractive. Also, not all sovereign debt is issued in the home countries currency, which means that the printing press doesn't help. US debt is very large, interest repayment are close to military spending. Without the reserve currency that would get worse. Something like 68% of world holding is dollar 17% Euro, nothing else of note.

The other side is that as there is a demand for dollars. The value of the currency is higher than if it wasn't which increases the price of exports and reduce price of imports. Trump might want to weaken the dollar.