The ape afraid to look his challenger in the eye isn’t the alpha male of the troop.
Or at least not for long. Ask the expert.
Update Nick Burbules at PBD suggests that McCain was mostly trying to keep his temper in check, and feared that he couldn’t do so if he looked at Obama That could well be right. Of course, a man so lacking in self-command is not to be trusted as Commander-in-Chief.