> EU countries went from killing each other in two of the most deadly wars to having a union in 30 years.

Was that the halcyon period where they were too broken to fight back and got the continent split between the Americans and the Communists? Or the modern period where it turns out the security situation in Europe was so totally mishandled that we ended up with the Ukraine war?

The spectre of nukes getting used isn't dropping over time and this sort of grinding destructive war is probably raising the risk of a big conflagration. Everyone seems to be rearming.