Why would Mattera care about Berwick? Because President Barack Obama recently appointed him to an incredibly powerful position as administrator of the Centers for Medicare and Medicaid Services - ground zero for ObamaCare. Congress had no opportunity to question Berwick's appointment; Obama simply appointed him to a new post as Medicare/Medicaid Czar, with a budget bigger than the Pentagon.
With transparency like this, no wonder Democrats are about to lose both houses of Congress. It will be interesting to see what evidence of further corruption the Obama impeachment hearings produce.