The national debt is completely meaningless. There are lots of drawbacks to excessive spending, like inflation, but the debt doesn't matter. Nobody's coming to collect the bill. It's doesn't work the same way as personal debt.
Do you seriously think that just because debt collectors aren't going to come break our collective kneecaps, that means the national debt doesn't mean anything at all? You do realize we make payments on that debt, right? How many credit downgrades should we be expected to ignore?