To some people, the chief financial problem for the U.S. Postal Service is the requirement it pre-fund health care benefits promised to future retirees. To others, the issue stems from not covering those costs as they arose, which resulted in the obligation becoming a debt.
Optimally, those liabilities should have been treated as a labor cost when they were accrued. They weren't, and Congress put the Postal Service on a path to fully fund the obligation over 10 years. Due to the recession and competition, that's become increasingly difficult to do - which is why the Postal Service defaulted on a $5.5 billion payment toward pre-funding last week.
Perhaps the best way to keep taxpayers from directly covering the billions in accrued, unfunded retirement benefits is to privatize the Postal Service. The balance of the unfunded obligation would reduce the sale price, but then taxpayers would be off the hook.
Except, of course, for governmental entities that also have retiree benefits which haven't been funded in previous years and aren't being funded now. Such benefits are real debts, and should be paid on an ongoing basis, just like actual payroll. When these costs are put off, they still accrue, and can lead to irresponsible obligations - just as with federal deficits and the national debt.