is an Emmy, Peabody and Alfred I. duPont Columbia Award-winning documentary filmmaker. For nearly 30 years, she has been producing and directing documentaries about American culture, history, politics, sports, art and music. In collaboration with co-director Ken Burns, she has created more than 80 hours of acclaimed programming for PBS, including "The Vietnam War," "Baseball," "Jazz," "Frank Lloyd Wright," "The War" and "Prohibition."
Mass incarceration — and its catastrophic disproportional impact on African Americans and people of color — for me was an abstraction until I walked into...