The non-aggression principle (NAP) is one which many libertarians accept, but few can defend. It states that it is wrong to initiate force or threat of force. This is, for situations where it applies, meant to replace a moral analysis.
Morality is knowledge about making choices. It tells us which are right and wrong to make. It tends to be quite complex, and we certainly don't know everything about it.
Now, to assert the NAP requires some argument that, in all situations, the right choice is not to initiate force. Regardless of the details. I've never heard such an argument. Does anyone know it?
(I know some people like the spirit of the NAP, and don't actually pay attention to what it says. I don't think they should support it, but acknowledge they don't need the argument I request.)
And don't tell me the NAP is right because it's self-evident, or I will have to WRITE BIG CAPITAL LETTERS AT YOU. mwahahaha!