It hardly matters whether Christie knew
So far, Christie's defense has been to blame his staff and claim he didn't know what they had done:
But it hardly matters whether Christie knew or not. Even if he didn’t know (and the average voter will never find that credible), it means he’s the kind of leader who creates an atmosphere in his organization where subordinates expect to get away with this kind of action or even consider it the norm. That says almost as much about his character as if he had ordered the spiteful act himself.
And don't forget -- there's more where this came from. Whether the bridge disruption was Christie's act or merely the act of the kind of staff he assembles, it can't be a completely isolated case. He or his people have almost certainly done such things before (more on that here, found via Progressive Eruptions). If the media don’t dig it all up before 2016, the Democrats will, if Christie is the Republican nominee.
Smart Republicans know that.
As a 2016 contender, Christie's finished.