Libertarians are ingenious folk. And I have no doubt that, given sufficient time, they can think up a host of ways to tweak, tinker, and contextualize the NAP in a way that makes some progress in dealing with the problems I have raised in this essay. But there comes a point where adding another layer of epicycles to one’s theory seems no longer to be the best way to proceed. There comes a point where what you need is not another refinement to the definition of “aggression” but a radical paradigm shift in which we put aside the idea that non-aggression is the sole, immovable center of the moral universe. Libertarianism needs its own Copernican Revolution.
Source: Six Reasons Libertarians Should Reject the Non-Aggression Principle | Libertarianism.org