For decades, white residents have left urban areas for the suburbs, changing the racial make-up of America's cities. Now, in some cities, the trend has reversed. As the racial balance shifts in historically black neighborhoods, new arguments are brewing over race, class, culture and identity.
Conor Dougherty, staff reporter for The Wall Street Journal, author of The End of White Flight
William Frey, demographer for the Brookings Institution
Gavin Newsom, mayor of San Francisco