I ran this clip some time ago, and just checked to see if it was still available (YouTube videos notoriously go missing, right when you want to watch one). It's still there. And it's still ten kinds of funny.
This author of this clip has taken footage of John McCain, and replaced the soundtrack with one of The Simpsons' best "rambling Grandpa Simpson" stories. Throw in the Matlock theme song, and you've got comedy gold! Although, to be fair, Sarah Palin is much more guilty of the wandering sentence. Anyway, enjoy. Even if it's for the second (or third, or fourth) time!