Yep, sure is possible. But all it takes is one unstable leader, or the failing of governmental structures designed to promote stability, or a few flaky sensors erroneously claiming a nuclear attack, and the meta-stability of MAD can tunnel to the true potential minimum, where nobody can wage war because we're all dead.

The modern world is unaware of how terrible major wars and nuclear weapons can be, because we are now generations removed from the experience. I fear that we are poised to re-learn some of those lessons.

Circling back: Yep, sure is possible, but I'm not going to work on weapons systems unless we are at war. I'd rather work on the education and science needed to help everyone respect one another and lead healthier lives. I've only got one life and don't want to spend it building systems that might end others' lives more-efficiently.

Keep in mind that the existence of lots of skilled people who are willing to contribute to serious war efforts, but who'd rather do other things most of the time, has some deterrent effect on foreign countries--there is an incentive to avoid doing something bad enough that it "wakes up the sleeping giant". I'd reserve criticism for the few people who aren't willing to help even in nightmare scenarios.

I think its more about what do you want to leave behind you ....sure, a given defense technical discovery or innovation may, in the right circumstances, used by the right people, prevent suffering, but, if your goal is to help others it seems a lot more direct to be a teacher, or a doctor, etc.