A National Debt Of $14 Trillion? Try $211 Trillion

"If you add up all the promises that have been made for spending obligations, including defense expenditures, and you subtract all the taxes that we expect to collect, the difference is $211 trillion. That's the fiscal gap," he says. "That's our true indebtedness."

We don't hear more about this enormous number, Kotlikoff says, because politicians have chosen their language carefully to keep most of the problem off the books.

"Why are these guys thinking about balancing the budget?" he says. "They should try and think about our long-term fiscal problems."