Summary: A key part of the Biden administration's plan to distribute free COVID tests depends heavily on the United States Postal Service. White House officials say that effort is going well, with tens of millions of tests now being shipped. But the U.S. Postal Service remains under intense scrutiny for its service, delivery, its finances and how its workforce is dealing with COVID. Geoff Bennett reports. PBS NewsHour is supported by - https://www.pbs.org/newshour/about/funders
