Turns out you're on to something, tomcat:

When a person makes very little eye contact, they may be feeling insecure. They may also be lying and not want to be detected....

Blink rate tends to increase when people are thinking more. This can be an indication of lying as the liar has to keep thinking about what they are saying. Realizing this, they may also force their eyes open and appear to stare.

Blinking can also indicate rapport, and people who are connected often blink at the same rate. Someone who is listening carefully to you is more likely to blink when you pause (keeping eyes open to watch everything you say).

Beyond natural random blinking, a single blink can signal surprise that the person does not quite believe what they see ('I'll wipe my eyes clean to better see').

Rapid blinking blocks vision and can be an arrogant signal, saying 'I am so important, I do not need to see you'

Source.

The last one was particularly troubling to me. As I watched, I saw that McCain never looked at Obama, and I thought that was strange. Later, I read that it was an effort to dehumanize Obama by simply not acknowledging his presence. At first I thought that was a real slight to Obama, and of course, it is, but it more than that. It is also a remarkable insight into the person McCain is, and how he self-protects.

Now just think of that personality representing America on the world stage. From the international viewpoint, first we've had 8 years of aggression and arrogance, possibly to be followed up with a man of cryptic insensitivity.

I'm sure McCain used detachment to make it through his captivity. The question is why would he use it as a tactic against Obama?