What about pre-emptive defensive? Defense from uncertainty? Defense from economic hardship?
(Whoa! I really just meant to raise the questions, especially in the case of justification for recent US military conflicts. I'm not advocating for anything!)
By which you mean attack before someone can attack you? Attack if you’re feeling uncertain about the prospects and outcome of diplomacy? Attack to acquire/open new markets to keep fueling the pipe dream of unfettered and constant economic growth?
Each of these notions are but rationales used to start a fight, not defend against one.
Those are very easy argument to make. But its very hard to find cases where they apply.
Once in a while you have a case where it makes sense, but very seldomly.
Most of the time you are much better at defending against uncertainty and economic hardship by putting some money assied rather then building a bunch of tanks.
I am sorry to say that in my view, such an answer implies that you are either extraordinarily naive or nationalistic.
In both cases, I see no way that we could ever agree.