Political Betting's Mike Smithson makes a good point about Sen John McCain's age and the effect viral videos might start to have if he continues to have "senior moments" over the next few months.
Those of us who are of a certain age will remember the way Ronald Reagan was lampooned for being a few cents short of a dollar (this is before his illness set in) and his age was certainly starting to be a concern. I remember him calling Princess Diana "Princess David", and that was just the tip of the iceberg. There is a real danger that McCain's campaign might start to fall apart as mental tiredness sets in throughout the campaign.
This YouTube video is the example used on Political Betting.com to make the point.