Ex-Medicare chief Don Berwick joins liberal think tank

Obama nominated Berwick, a well-respected health expert and pediatrician by training, during a congressional recess in July 2010 because Senate Republicans would not confirm him. Republicans latched onto controversial comments Berwick had made in favor of Great Britain's government-run National Health Service as the focus of their attacks against him. 

Berwick stepped down as head of the Centers for Medicare and Medicaid Services last December.