Tonight Drudge juxtaposed these three photos on his site as he linked to articles about each politician. I was struck by the similarity in their body language. Actions speak louder than words, so I searched the body language blogs to see what we might learn from the experts. Instinctively, of course, we all know what this finger wag means. However, there's nothing better than getting confirmation from experts.
Mothers and teachers are common users this hand gesture. In general it is used to admonish or warn a single individual. It is a variation of the "you" gesture. If translated into language it would say. "Stop whatever you are doing and pay attention to me. I am your superior and I am warning you!" Classed as a "silent" parent to child gesture, it is completely unacceptable in a professional environment where it will be interpreted as both rude and domineering. Some psychologists believe that it is a metaphor for the cane or whip.