Using every weapon at your disposal would entail, at the extreme end, unleashing weapons which could viably kill every person on this planet - to defend a state. It's not exactly a typical foundation for pacifism.
Well, if it helps, I'm a Computer Scientist so I can't think of how to destroy the entire world with "every weapon at my disposal". I reckon at most I could make a more lethal drone swarm.
EDIT: Oh, I should clarify, that's where all this stuff about pacifism comes from. I did some research on autonomous AI for robotics during a post-doc and that made me think more carefully about somewhat extreme situations that would hopefully never arise, and how I would react to them. I mean I was already thinking that way but the hands-on experience and real, if distant, possibility of my work being used in ways I would never want it to be, helped solidify those earlier thoughts into a more coherent form.
I'm saying because given my username you might legitimately wonder whether I would actually ever be in the position of taking up arms, like actual weapons, to fight for my country. Probably not. But programming or piloting drones is absolutely not out of the question, as a thing I'm qualified to do. So I had to think about whether I'd do it, and under what circumstances.
I'm also a signatory of the Lethal Autonomous Weapons Pledge which I signed during my PhD:
