One of the main challenges of maintaining peaceful international relations is the escalation of distrust and the ensuing arms race.
The possibility that others might attack you is a reason to arm yourself. But this step will in turn be interpreted as a threat by the other, who will in turn arm itself (even more). Etc.
Aren’t there ways to simply invest in purely defensive weapons? So that your efforts to remain safe do not in turn threaten others? Which in turn allows others to also de-escalate?
In other words, are there military set-ups that are useless for offensive actions but good enough for defending a country?


There is no such thing as a weapon that is only capable of being used for defense. It’s a logical contradiction on the order of a true paradox such as “this statement is false”. It is theoretically possible to have some sort of defensive shield with no way to move it, but even such a thing could be deployed offensively as an area denial tactic, ask any rts player. If you can stop force, it can be used as force.
Another way to think about it is the old question of which would win, the proverbial unstoppable force, or the immovable object? Einstein’s theory of relativity gave us a framework to say that both terms refer to exactly the same thing. An immovable object, by definition, is actually an unstoppable force. And an unstoppable force, by definition, is an unmovable object.
So it goes with weapons. A weapon is a weapon by its nature. It is only the wielder who decides if it is defensive or not. If you can’t trust the wielder, then you can’t trust the wielder, and that’s basically it, and the root of all problems.