A reader writes:
I think your reader is confusing deficit with debt. Setting aside whether we could really get to zero if we're in Iraq for 100 years, the math does add up. By zeroing out deficit spending on the war, you reduce the deficit. In the credit card example, 10k a month is the deficit. Not adding 10k the next month does indeed reduce the deficit for that month, which is the amount of debt you're adding. You simply don't do anything to get rid of the debt.
Hilzoy crunches the numbers.