Audience members sing during the benediction for the 50th Anniversary of the March on Washington where Martin Luther King, Jr., spoke, Wednesday, Aug. 28, 2013, in front of the Lincoln Memorial in Washington. (AP Photo/Charles Dharapak)

Marking 50 years since 'I Have a Dream'

President Barack Obama won’t need to mention race — a subject he doesn’t talk a lot about in public — when he stands at the Lincoln Memorial…