> Moreover the late 19th and the first half of the 20th centuries taught us that focusing on the nation-state leads to widespread warfare. Better to have those nation-states in economic cooperation that leads to peace than economic competition that leads to war.

I think it has taught us the opposite? Pre WWI, the world was already very integrated and globalized, to the point that many pundits said that a large war is impossible, because it would hurt businesses everywhere too much. And yet it happened.