The FedGov has learned a nifty trick, it can now spend more and tax less at the same time! It is called deficit spending, aka, borrowing massive amounts of money on the open market. This heavy borrowing distorts the credit market and pushed up interest rates.
This 'decoupling' of spending and taxation is addicting for government but quite obviously can't go on forever.
These people are being paid interest but we're borrowing the money to do it.
Barrowing to pay interest on previous debt is not recommended by anyone I know.
If there is a crises of faith in the dollar, these folks may want more than just interest, they may want their principle back, too. This would cause financial collapse and turn us into a third-rate nation overnight.
Who of all the candidates has a tried & true plan to make the American dollar the envy of the world (again).