To offset the debt that Congress has forced on them by requiring them to pre-fund pensions and healthcare cost for employees who don't exist yet. And Congress s

To offset the debt that Congress has forced on them by requiring them to pre-fund pensions and healthcare cost for employees who don't exist yet. And Congress sets postage rates as well, so USPS can't raise rates in order to pay down their congressionally-mandated debt without getting approval from Congress. And the requests to raise rates are often denied.