> 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?

What do you mean by this? Ukraine is not part of the EU.

I mean the EU got its diplomacy so badly wrong that it sparked one of the deadliest wars this century in Europe and the EU countries appear to be rearming in preparation for the state of war spreading. The EU seem to be in the process of destabilising the state that controls the largest cache of nuclear weapons in existence.

The project has not scored well on matters of war and peace. And there is still a far too likely possibility here that after re-arming and in an era of war the Europeans fall back to their old tricks and descend into a state of war against each other again, given that the adults keeping them peaceful seem to have left the building.