If a smidgen of suspense lingered earlier today about whether much of the government would shut down tomorrow, there was never the slightest doubt that the U.S. Postal Service would skip a legally required retiree health care payment for the third straight year. Pretty much ever since the Postal Service defaulted on the 2012 payment, USPS leaders have been warning they would miss the $5.6 billion obligation due by midnight tonight; in another 15 minutes or so, the agency will officially be in default. Unlike past years, however, when an anxious Congress either cut the amount of the annual installment or pushed back the deadline, this year’s…