Well, think on this.
The President persuaded the fed to lower interest rates to 0% or near 0%. The fed can now float bonds at near 0% interest and use that money to retire existing bonds with a higher, real rate.
The end result is federal debt at no interest.
If there is no interest then the budget deficit due to debt interest goes to $0
Now, is that a deal or what?
Existing bonds are non-callable. They can’t be retired.