This is really misleading. Much of that "debt" is in the form of obligations to U.S. citizens. For example, the $52T in social security/medicare is only an obligation because the government has promised to pay people like you and me. That's $52T we have to pay, but it's also $52T that we'll be receiving.

The same goes for derivatives. Every liability on someone's books is an asset on someone else's. The real problem is that with all these financial firms going belly-up, we don't know who's holding the debt and who owes it.