Leonard Pitts: How did we ever forget this song?

It’s like listening to a song you used to know.It’s an old sweet song, a hymn of hope and possibility. It’s a tune you haven’t heard in far too long.That’s how it is when Rev. Dr. William Barber speaks morality. It’s not just that Barber, pastor of Greenleaf Christian Church in Goldsboro, N.C., and organizer — with Rev. Dr. Liz Theoharis — of the new Poor People’s Campaign, is eloquent. No, it’s that he reminds you how rare it has becom