The Caucus blog (NYT) observes a couple of the misstatements on the podium in Springfield Ill. as Joe Biden and Barack Obama spoke --
As he wrapped up his podium-pounding peroration, Mr. Obama turned and said, “So let me introduce to you, the next president, the next vice president of the United States of America - Joe Biden.”
Mr. Biden returned the favor near the end of his own remarks. He paid tribute to “the next president of the United States - Barack America!”
But think about it: "Barack America" is a good one. It sort of sounds like Obama, which of course is why Biden's wires crossed when he was saying it, but it's way better than Barack Osama, and it neutralizes the stylized fact that no American president's surname has ended in a vowel. If the country's name ends in a vowel, why can't the president's?