You are guilty of one of my pet peeves. Obama never said there were 57 states.
He said that he’d been to 57, and had one more to go, but that his staff wouldn’t allow him to go to Alaska or Hawaii. So, he actually said there are 60 states.
I heard the original too but have been going along with the misquote. Either way, the excuse given that “he was just tired from campaigning” doesn’t fly. I’ve been very tired before too but would not make such a statement. Even if drunk too.