Bryan Caplan's summary of Chapter 2 of Murray Rothbard's classic For a New Liberty reminded me of one of the reasons I'm not that kind of libertarian. It starts with the fact that I can't grasp how fraud counts as a violation of the “non-agression principle” while other ways of manipulation of another's will don't. I can't grok the conception of coercion that includes lying to someone in order to get something but leaves out, say, the threat to withdraw intensely valued affection in order to get something. A credible threat of emotional distress seems a lot closer to a paradigm case of coercion (a threat of physical harm, e.g.) than does a misrepresentation of facts.
Even when I was a believer in Rand/Rothbard-style libertarianism, I found the 'or' in the “no force or fraud” formulation of the non-coercion principle a bit vexing and suspect. It seems too frank an admission that fraud isn't force or agression at all. It's another morally questionable way to get someone to do something they might not otherwise choose to do. But there are yet still other morally questionable ways to get people to do things. Why not add more 'or's?
Now it seems to me that non-coercion libertarians tend to reason backwards. You start with a list of kinds of action considered impermissible, struggle to classify them all instances of coercion, and then say that your philosophy is based on non-coercion and not on whatever principle (if there was one) that led you to try to include some classes of actions (that are not intuitively coercive) but not others (that seem pretty coercive) under the coercion rubric.
I guess this is just another way to make my complaint about fake libertarian clarity. Let me just say that because I think emotional coercion is coercion doesn't mean I think the state should try to stop it. And just because I think fraud isn't coercion doesn't mean I think the state shouldn't try to stop it. What I think is that some coercive actions (emotional blackmail, e.g.) should be legal and some non-coervice actions (fraud, e.g.) should be illegal. Which is to say, I don't think the notion of coercion can be made to do the work many libertarians want it to do.