As public schools have re-segregated, the achievement gap between black and white students has widened. That's a major finding from a forthcoming year-long investigation into southern schools by Pro Publica reporter Nikole Hannah-Jones who yesterday previewed the article on Face the Nation. The 20-minute Sunday morning segment comes after last week's civil rights summit featuring four presidents--Obama, Bush, Clinton, Carter--reflecting on LBJ and the 50th Anniversary of the Civil Rights Act of 1964.

Other guests on the program, which assessed failures and progress made: Michael Eric Dyson, Evan Wolfson, and Tavis Smiley.

So, how are we doing 50 years on?