I was recently on a plane, and while I was reading books the entire flight, there were small TV screens up above that were showing a few TV shows. Every once in a while I'd glance up and catch a few seconds of soundless video. At one point, the show on was 1600 Penn, which I knew was about a family in the White House (with the president played, as is only fitting, by Bill Pullman--he who gave us the greatest presidential performance ever caught on film).
Anyway, the moment I happened to see from 1600 Penn was of the actor Andre Holland, who plays the White House Press Secretary, standing at a podium in the West Wing taking reporters' questions. And the first thought to pop into my head was that, even though I technically knew that Bill Pullman was the president in the show, Andre Holland must be the president--because, you see, Andre Holland happens to be black and thus look more like Barack Obama than Bill Pullman does.
The small fact that my brain subconsciously assumed the black person was the president seems in some way huge to me. Of course we all knew in 2008 that anyone--black, white, Asian, latino, male, female, etc.--could be president, until January 20, 2009, for the most part we all subconsciously pictured "The President" as a white dude. Because that's how it had always been.
Say what you will about his policies; I'm immensely grateful that Barack Obama has helped us all understand more viscerally that anyone really can be president.