Question is too clever by half, but Obama's immediate response is affecting: "My wife could tell you all about that." Says "country" when he means to say "world." Talks about the American Dream, and its accelerated decrepitude in the last 8 years. We can't fix it if we keep doing the same things (implicit: as McCain will do.)
With his last words, McCain raises the specter of the unknown, and talks about how he was raised by a single mom, too, because dad was at sea. Trying to project toughness and patriotism. "I'm asking the American people to give me one more opportunity."
And then, an interesting use of the past tense: "The great honor of my life was always to put my country first."