The USPS is facing a severe fiscal crisis because it is required to make a $5.5 billion pre-payment to a retiree health benefit fund, and has said it cannot make the payment. The USPS was originally scheduled to make that payment by Sept. 30, but the continuing spending resolution approved by the House this week extends that until Nov. 18.

The Baucus bill, S. 1649, would require the Office of Personnel Management to estimate how much the Postal Service has made in overpayments to the Federal Employee Retirement System and use those to make its payment to the health benefit fund. Baucus said some estimates put the overpayment at $6.9 billion, more than enough to make the payment.

The bill also includes language that prohibits the USPS from closing rural offices if there is not another post office within 10 miles. Baucus just this week complained to Postmaster General Patrick Donahoe that the USPS is planning to close three rural offices in Montana, a decision Baucus said was made without allowing for enough public input.

"It is clear that the Postal Service decided to close these post offices without sufficiently considering community input, and I oppose moving forward with the closings until Montanans have more time to voice their support for their local post office," he wrote in an Oct. 3 letter.

Baucus added that while Donahoe has said the USPS would only make closure decisions after substantive consideration of public input, "this has sadly not been the case" in the instance of the three Montana offices. He also noted that nearly all of the 85 offices in Montana that might be closed are more than 10 miles from another office.

-- This story was updated at 11:45 a.m. to correct that the USPS payment is now due November 18.