The Non-Aggression Principle is the fundamental requirement for being a libertarian. If you accept it as valid, then you are a libertarian. If you don’t, you aren’t a libertarian.
But what is it exactly? Nothing more (and nothing less) than the agreement that you will not use violence against other people other than defensively (to protect yourself, your possessions, or another innocent person). This means that all people have the right under the NAP not to have aggressive violence used against them, even if they themselves do not accept the NAP.
The NAP is not pacifist. You can use (an appropriate level of) violence against other people to defend a value. E.g., self-defense is not a NAP violation, but holding someone up with a gun to get their wallet, or for that matter shooting them just because they annoy you, is a NAP violation.
Having said that, there seems to be some confusion about what the NAP does and doesn’t imply.
1. What it does imply: That people who follow it will never be in a position to have defensive violence used against them, because they themselves do not employ aggressive violence. Thus, any violence used against them must be aggressive rather than defensive, and therefore will by definition be prohibited by the NAP.
2. What it doesn’t imply: that people who follow it are behaving in a moral way, i.e., that that their actions are morally right or socially acceptable. That is, a person can follow the NAP but still be a jerk. In that case, others still can’t use violence against that person without violating the NAP, but those others can shame, boycott, or use any other non-violent means to teach that person a lesson.
3. Also please note that actual violence or a credible threat of actual violence against a person or people is required to violate the NAP. Mean words or even very nasty actions like doxxing someone, don’t violate the NAP, although they are still bad actions.
What does this mean? It means that just because some action doesn’t violate the NAP doesn’t mean it is a good or socially acceptable action. Groups have rules that often require considerably more than just following the NAP. For example, you can be thrown out of a group for calling others names or advocating violence, even though neither of these violates the NAP. More generally, you can follow the NAP while disregarding the Golden Rule, although it is advisable for many reasons to follow the Golden Rule to the extent possible.
Note: “people” and “person” refers to entities that are capable of agreeing to accept the NAP. To the extent of our current knowledge, the only entities that satisfy this requirement are members of homo sapiens. If it can be demonstrated that there are animals, aliens, or AI entities that can accept the NAP, then it would apply to them also.
I like the clear presentation. It provokes many thoughts, none very organized yet, so I won’t dump them here.