A sign of guilt.

It's very easy to determine if Christie knew anything about the bridge closing. The Governor has such a uncontrollable temper that if he didn't know he would be in a constant state of anger. He would be red-faced furious 24 hours a day for having been put in this scandalous position by his minions. Bridget Kelly's head would have been only one of many to roll. He would appear hurt chagrined, mystified, in short, innocent. The fact that he is relatively calm is, as far as I'm concerned, a confession of guilt. An innocent Christie would be tossing chairs, yelling at everyone in sight, and acting the part of a misled governor.