Integrated markets and commerce is why we have had peace in the western world. The very things the current American head honcho is tearing apart.
We have had very little peace in the rest of the world in the meantime between the colonial wars, the various proxy wars of the Cold War, then the numerous stupid adventures of the modern America and now Russia wanting to be an empire again.
I don’t think integrated markets were the cause. There was plenty of integration between Ukraine and Russia in the oil and gas infrastructure for example.
(Nuclear) deterrence is why we’ve only had proxy wars instead of direct wars