I've gone to see Obama at three different rallys. Two out of the three times I nursed in the front row (yes, I'm a huge supporter so I got there early for the best seats! It's good, though, he remembered me the second time!)
The second time I was there nursing, there was a woman sitting next to me who was wearing a sling and nursing her 6 week old. Obama, about 10 feet in front of us, smiled and waved. I don't know his official stance, but it was kinda cool that he acknowledged it.
Eventually he's going to think I go just to lift my shirt.