Lots of people have been writing about Obama's temple, and there's a lot of speculation about what it represents. I think the obvious answer though is that the stage is a reference to Lincoln Memorial, where Martin Luther King Jr. gave his famous "I Have a Dream" speech 45 years ago today.

Obama's temple

Lincoln Memorial
Barack Obama has also included both MLK and Abraham Lincoln as two of his heroes on numerous occasions. Naturally Obama wants to visually recreate that historic speech, staring himself in the role of Martin Luther King Jr. QED.