False. Airlines are not allowed to have guns on flight. The government has forcibly prevented airlines, their employees and their passengers from defending themselves through the use of guns or whatever other means they might find appropriate. It therefore has usurped the right to self-defense in the specific case of 9-11 and therefore whatever actions it may take in consequence are illegitimate.
what I meant by "self-defense" is national defense.
I disagree. You used the term “self-defense” because it is the proper one. National defense is a derivation of self-defense, a form of collective self-defense. The concept cannot be justified – at least not from libertarian premises – in any other fashion. A government which has usurped the right to self-defense and replaced it with a concept of national defense is not based on the principles of natural rights. Its actions cannot be based on natural law.
On the individual rights level, retaliatory violence is not initiated violence, hence is justified against anybody. So, on the national level, retaliatory war against any entity that attacked American citizens is justified.
What is this concept of “retaliatory war”? How does it relate to defense of any kind, especially in the context of 9-11 where it is not the least clear who was responsible for the action? Who are you retaliating against? Afghani peasants?
in matters of foreign policy the government should do whatever it thinks our national interest is, and the voters can provide a correction every election cycle. That is not the same as saying that it should do whatever the majority wants.
This is gobbledygook. I’m not sure whether you are arguing in favor of a form electoral dictatorship or majority rule. To this I repeat what I said in #146. “But then your argument is neither libertarian nor objectivist. For that matter, it’s not even constitutional.”