My Lai massacre, 50 years later: Jonathan Berger’s opera captures the madness

“Where in God’s name is the medic?” the dying hospital patient demands. He’s not asking for help for himself. He’s frantically trying to save a boy’s life. It’s a scream, one of the important screams in American history, that has haunted him for 38 years.

Jonathan Berger’s opera “My Lai” — written…