- it does not matter at all, as long as inflation is under control (MMT)
- it's fine, as long as the long run average is ~zero (a cyclic argument)
- it's fine, as long as the long run average is a small stable % of GDP
- we have to balance the budget every year, no matter what
I don't think any serious person holds the last position.
I think this is theoretically viable only if debt % is lower than growth rate. Recently US debt % of GDP has been higher than growth rate.
The scale is completely different. Economics do not simply scale up and down, the math changes drastically when the numbers get bigger.
Yes, the scale is different. This means that the debt problem can go on for far longer without being apparent. It can even be put off until the current slate of politicians are out of office, until they're dead of old age and beyond accountability. Scale can hide things, by making them so big your field of vision doesn't allow you to see it all at once.
And yet, that's the only position that (were it followed) would see us free from ruinous debt. What are we paying in interest every year again?