But wagging is not always positive.

Wagging is different than waving.  It's polite and proper to wave, but it's not proper to wag at everyone.  Your spouse should not be given secondary importance. 

Which brings us to the purposely diverting attention ...which could apply to affairs, or even the affairs of a nation.

Which was the case in a movie by this title ...making a situation seem like something that it is not.

You see the tail wagging and assume the dog is wagging it.

As the saying goes:

Why does the dog wag its tail?

Because the dog is smarter than the tail.

If the tail were smarter, it would wag the dog.

I hope the tale of hope and change is not smarter than you ...as it is working to change our Constitution, our faith beliefs, our morality (if you feel that is different or non-related to faith ...I do not), and our integrity as a nation.