Adam Knott's article at liberty.me purports to see a primary shortcoming for the non-aggression principle.
"Many libertarians, Knott begins, "define their libertarian philosophy in terms of the nonaggression principle," aka ZAP for the zero aggression principle. The principle, variously stated, proclaims that no one has a right to initiate force, intimidation or fraud against another.
A couple of definitions are in order. If we can't agree on the meanings of our words no discussion is possible.
2. Government, because it rests on taxation, which is the taking of money from individuals who have not explicitly voluntarily consented to that taking, is a criminal enterprise based on aggression/coercion.
Knott's "shortcoming" example is that libertarians disagree on patent and copyright laws, some claiming that enforcement of such laws constitutes aggression while others contend that anyone who uses your patents or intellectual property without your explicit consent is the aggressor.
But under the non-aggression principle patent and copyright laws constitute aggression only if they are enforced by aggression, as for example by government. If patents and copyrights can be enforced through voluntary means then there is no conflict with the non-aggression principle.
Knott then posits that this is a definitional disagreement among libertarians that stems from wants vs. ends, and sites Spinoza and Mises and then quotes Bohm-Bawerk:
"We originally want or desire an object not because it is agreeable or good, but we call it agreeable or good because we want or desire it."
Knott then concludes from this, "Similarly, we add little to our knowledge in stating that libertarianism is based on nonaggression. In doing so, we merely substitute disagreement on what constitutes aggression for disagreement on the kind of society we each desire."
What Knott and many other libertarians seem to miss is that these wants, wishes, longings and desires are irrelevant because the non-aggression principle isn't about what we desire; it's about our actions.
Wanting your money because one finds it desirable or good or agreeable doesn't violate the non-aggression principle. Stealing it does while entering into a mutually satisfactory trade for it does not.
There may be legitimate shortcomings with the non-aggression principle worth considering but Knott's short essay fails to address any.
To repeat: The non-aggression principle is about our actions, not about our feelings.