I think this has largely proven true, and as certain supply chains look to onshore, this can have geopolitical implications.
[0]: https://en.wikipedia.org/wiki/The_World_Is_Flat#Dell_Theory_...
How would you demonstrate such a hypothesis was true?
The whole issue with the Yugoslavian and Soviet states was that they weren't separate states with trade relations but were instead held together as single nations by force.
Russian McDonald's have since been rebranded, so it remains kind-of true when viewed as state instead of cause-effect. I imagine the truth to these general statements is more like, McDonald's never opened a franchise in two places that were at war with each other.
And lack of it would have meant easier and multiple wars.
deterrent are a vital part of peace. And peace is like a stack of cards built on multiple deterrents.
you can see examples of lack of deterrent during history when wars where happening on the desire of a king and you can also see the beginning of deterrent working when kinds and queens married their children between them to keep peace going as long as possible.
Trade generally? Sure, but we have centuries of wars happening despite international trade so it's obviously not the sort of panacea people make it out to be. McDonalds specifically making countries think twice about war? Please. Shitty burgers are not that important.
More about countries trading important things between them or having dependent economies.
I'm pretty sure the McDonald's theory of war went out the window with the NATO bombing of Yugoslavia.
I fully acknowledge the unfalsifiability of the above as well.
"Who was Germany's biggest trading partner prior to the outbreak of World War 2? France"
When I was younger I considered economic sanctions a far preferable alternative to the brutality of kinetic warfare, in line with the prevailing view of western statecraft. Over time I've come to think it's significantly worse, little more than a form of state terrorism in which populations are politely murdered. While the architects of such policies talk about accountability, containment, etc in reference to unfriendly leaders they'd like to displace, starving children and blaming it on someone else is fundamentally genocidal and in my view constitutes a grave moral crime. I was disgusted by the eulogies heaped upon the late Madeline Albright, because when I think of her I can only remember her assertion that the deaths of 1/2 a million Iraqi children in the 1990s was 'worth it.'
It might be fair to say economic entanglement is a risky strategy for peace because depressions can always come along, but I don't know it's fair to say that economic entanglement doesn't improve the odds of peace if our counter-example is a global breakdown.
The most effective deterrent to war is to put the fear of death in the people who decide whether or not to start wars. MAD theory, while technically wrong, was a good enough story that it averted several catastrophic nuclear attacks. If only because the people with their fingers on the buttons second-guessed themselves long enough for reports to come in that it was actually just the light reflecting off the ocean and not an incoming American ICBM.
[0] Yes, I mean this in the same context that one might refer to a technological singularity. Social existence today is a nested hierarchy of supra-individual social structures, of which superhuman AGI will merely be one of its subagents.
[1] Though they did come close in the 1800s over Staten Island. They call it the Empire State for a reason.
The premise of The Great Illusion is that international trade is a very good deterrent to war. The book doesn't argue that it's an 'okay-ish' deterrent to war, it claimed that WW1 was extremely unlikely to occur and that if it did, it would be over quickly. Not only did WW1 happen, so did WW2 a few years later. Neither war was short, and even more and bloodier wars after WW2 would have been a damn good bet if not for the invention of nuclear bombs.