I have a “nutshell” summary and critique of John Stuart Mill’s On Liberty now up at e3ne.org. Excerpt:
Mill thus defends freedom of conscience, speech, and lifestyle on completely “practical” grounds, but he leaves some significant loose ends in On Liberty. For instance, there are lots of examples of “harms” that the government shouldn’t regulate, like breaking up with a longtime boyfriend or girlfriend. It may cause emotional damage to break up with someone, but there’s no justification for forcing someone to stay in a romantic relationship. So the Harm Principle may establish a necessary condition for government regulation but not a sufficient one (in other words, the government should regulate nothing but harms, but not all harms).