1. Nation A is running a small current account deficit and its private domestic sector is saving overall. Nation B has a smaller external deficit (relative to its GDP) but its private domestic sector is balancing its spending and income. The governments in both Nations have to be running deficits.

2. Modern Monetary Theory (MMT) explains how central banks sell bonds to drain excess bank reserves in order to maintain their given interest rate setting. We know that the same outcome can be achieved by paying interest to the commercial banks on the same reserves. Ignoring any reserve requirements, this means that there is no need for government (via the central bank) to issue debt when it net spends.

3. The advantage of the government issuing bonds to match its deficit rather than just instructing the central bank to credit bank accounts in recognition of its spending intentions is that the private sector is wealthier as a consequence.