Pulitzer Prize-winning historian, Robert Caro, is one of the foremost scholars on Lyndon Johnson. The day of Barack Obama's historic acceptance speech at Invesco Field in Denver, which was also the 45th anniversary of the March On Washington and Dr. King's "I Have a Dream" speech, he wrote a fascinating opinion piece - "Johnson's Dream, Obama's Speech" - in the NYTimes on LBJ, voting rights and Obama. In short, Caro argues that Obama's speech might not have been possible if it had not been for another speech, made by Johnson 43 years earlier, a speech that was so powerful it made Martin Luther King, Jr., cry... It is worth a read.
The letters to the editor around the time of Obama's historic acceptance speech were also very interesting and worth checking out.