If McCain is going to go after Obama, as he should, a warm, sugary embrace at the start of tonight’s festivities would be a bad mistake.

The initial greeting between the candidates is something people watch closely. If McCain treats Obama like he’s a pal and then goes for the jugular, he will look terrible and be seen as phony. The idea is to shake hands in a way that conveys, “I’m polite but I’d rather be having a root canal than shaking hands with you.”

Full confession: I think we get too tactical here at the expense of the big picture. But I honestly think this makes a difference.