In Europe there have undoubtedly been international institutions going back a long way. Is what you're talking about really a blood ancestor of the EU, or is it a predecessor - another group that happened to have some of the same members.
As I recall, Churchill was a strong proponent of the EU's [edit: I can't believe I used the wrong word:] ancestor (the European Communities? Some oil and coal community?), as a way to prevent further wars. Churchill blamed nationalism specifically.
I would say it was because there is a reasonably direct line of succession in terms of both members and responsibilities. The steel and coal union is also in that line. What happened is that the unification was seen as beneficial but that a larger body with a more future proof organization was what really was required.
> What happened is that the unification was seen as beneficial but that a larger body with a more future proof organization was what really was required.
You're saying the EU wasn't required? That seems like a bold statement, but probably too much to sort out in HN comments.
I'm a bit confused by "but" in that sentence. I'm not sure if a 'not' or another word is missing there. Certainly many saw unification as beneficial - again, it was the key to many. Many still do.
Unification was underway prior to the EU, the EU is the eventual larger body but it took some steps to get to the point where it could be properly established, mostly on account of the various countries still reeling from WWII and being very busy with reconstruction efforts (and piss poor to boot, the first years after WWII were almost as bad as the last years of the war and in some places even worse besides the reduced immediate risk to life). Doubly so for those countries that ended up on the far side of the Iron Curtain, but then again, they weren't part of the EU for many years to come. But for many of them the only thing that changed is that German uniforms became Russian uniforms and usually that wasn't accompanied by a higher degree of civility by the occupiers.
Nonetheless, all of this was not the cause of peace being restored in Europe after WWII; it was the consequence of it. You could argue that the EU kept the peace, but I think that overlooks the role of NATO and of the hundreds of thousands of American troops who never actually left western Europe after 1945. For instance, do you really think there's a serious risk of war breaking out between the UK and France since the UK left the EU? Of course not.
> all of this was not the cause of peace being restored in Europe after WWII; it was the consequence of it
How do you establish the arrow of causality (and of course, to some degree, it points both ways)? Objectively, we know that a major intent and design of the EU (and its earlier iterations) was to prevent another war.
The one thing we know about the arrow of causality is that it doesn’t point backwards in time. The founding members of the EU all had friendly relations with each other prior to the founding of the EU. That’s why they formed the EU!