But the default again raises questions about whether taxpayers will eventually need to step in to save an agency that historically has gotten by without taxpayer support, even though it is subject to congressional oversight. 

That oversight has complicated the agency's efforts to overhaul itself. As it loses roughly $25 million a day, the agency has rolled out a plan to cut Saturday delivery, reduce low-volume postal facilities and end its obligation to pay the future retiree health payments. 

The House and Senate each have taken a different approach to that plan. 

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, in large part due to concerns among rural lawmakers over cutbacks in their communities.