The leader of the Department of Veterans Affairs health care system unexpectedly stepped down from her position effective Saturday, leaving three top VA positions unfilled by permanent undersecretaries. Dr. Poonam Alaigh, the acting undersecretary for health since May, sent a message to VA employees last week informing them she was resigning for family reasons. “I have made the difficult decision to step down,” Alaigh wrote. “I want you to know that it has been my greatest honor to serve [VA Secretary David Shulkin], each one of you and all of our veterans. As I prepare to now leave Washington, I...