If we have learned nothing from the last 5 years, Consumer debt becomes national debt when the consumer defaults. Banks lend, consumers borrow and then default. Debt is then nationalized to prevent the banks from going under.
I put it out there that while the national debt is quite large, there are much bigger problems of job loss and poor quality consumer, business and municipal debt which need to be addressed to prevent these debts from quadrupling the size of the national debt and killing our economy.