Pacifism as an ideology isn't opportunistic, it's the belief that war is wrong no matter what. So if you argue that successfully, then it won't matter to pacifists in the US or China or anywhere whether their enemies have become pacifists, they still won't fight.
i see that now.
The thought experiment was that you are a philosopher listened to by a global audience and don't know exactly which countries will be evil in the future.
Okay, I should’ve looked at it that way. I don’t think global pacifism could be achieved. Some groups would listen and would see no justification for war. But other groups are too greedy. They want too much and will be pragmatists instead of pacifists and can justify war as a means to an end