All parties, on left and right, believe in freedom. The question is whether there are ways of having too much freedom, or of using it in the very wrong way, so that it starts to hurt other things we care about, like prosperity, safety and happiness.

The issue comes to a head with internet pornography. The standard view is that people should be left to look at porn as much as they like, just as they should be left to buy guns, eat unhealthy foods, divorce and remarry eight times and make nothing of their talents: it's a free...