It was so surprising to see Henninger jump on board the Santorum train. It is a really significant endorsement, if you can call it that. Up until now, all the WSJ people have been in the Romney camp.
The article even explains why the libertarians should supporting Santorum, freedom vs. liberty just tempers the liberty with responsibility.
I have noted that Henninger has been off the Romney reservation at the WSJ. He has been arguing in favor of Santorum to some degree or another for a while now. This is by far his most forward argument for Rick over Romney. As you said, the WSJ is Mittensland and it is refreshing to get a blast of Conservatism from that paper once and a while.