Kathleen Parker: Democratic ticket knows how to use smile as a tactical weapon

When Biden and Obama project a Duchenne smile, it is indeed a sunny day. They both are blessed with dazzlers and both obviously have recognized the advantage this gives them in politics. Obama's legendary likability most likely is linked to his billion-buck grin.

To receive a warm smile is its own reward. To be on the receiving end of an insincere smile, or one that doesn't fit the message being delivered, is psychological trickery. Think of Nurse Ratched in "One Flew Over the Cuckoo's Nest." She smiled even as she delivered psyche-crushing information. The disconnect between what her victims were seeing and what they were hearing and feeling was torturous. Similarly, the teacher who smiles and says "Johnny made a bad choice" is confusing and potentially enraging.

Finally, a politician who smiles while trying to take you down may be a pro, but he's no friend.

"Who do you trust?" Biden asked Americans as he looked directly into the camera.

Well, now, funny you should ask.

Kathleen Parker's email address is kathleenparker@washpost.com.