The defaults won't stir any kind of catastrophe in day-to-day mail service. Post offices will stay open, mail trucks will run, employees will be paid, current retirees will get health benefits.
But a growing chorus of analysts, labor unions, and business customers are troubled by continuing losses that point to deeper, longer-term financial damage, as the mail agency finds itself increasingly preoccupied with staving off immediate bankruptcy while Congress delays on a postal-overhaul bill.
Postmaster General Patrick Donahoe has described a "crisis of confidence" amid the mounting red ink that could lead even once-loyal customers to abandon use of the mail.
"I think for my generation it was a great asset - if you had a letter or package and you needed it to get up to the North Pole, you knew it would be delivered," said Jim Husa, 87, of Lawrence, Mich., after stopping to mail letters recently at his local post office. Noting the mail agency's financial woes, he added: "Times have changed, and we old-timers know that. FedEx and UPS and the Internet seem to be making the Postal Service obsolete."
Banks are promoting electronic payments, citing in part the growing uncertainty of mail delivery. The federal government will stop mailing paper checks starting next year for millions of people who receive Social Security and other benefits, paying via direct deposit or debit cards instead.
First-class mail volume, which has fallen 25 percent since 2006, is projected to drop an additional 30 percent by 2016.
Art Sackler, co-coordinator of the Coalition for a 21st Century Postal Service, a group representing the private-sector mailing industry, said the payment defaults couldn't come at a worse time, as many major and midsize mailers are preparing their budgets for next year.
"The impact of the postal default may not be seen by the public, but it will be felt by the business community," he said. "Mailers will be increasingly wary about the stability of the Postal Service. The logical and likely move would be to divert more mail out of the system."
The Postal Service, an independent agency of government, does not receive taxpayer money for operations, but it is subject to congressional control. It estimates that it is now losing $25 million a day, which includes projected savings it had expected to be accruing by now if Congress had approved its five-year profitability plan. That plan would cut Saturday delivery, reduce low-volume postal facilities, and end its obligation to pay more than $5 billion each year for future retiree health payments.
While the Senate passed a bill in April that provides an $11 billion cash infusion to help the mail agency avert a default, it also would delay many of the planned postal cuts for another year or two. The House remains stalled over a measure that allows for the aggressive cuts the Postal Service prefers.