Just to give you some context, the idea in that theory is part of a broader strand of thinking called "capitalist peace theory". It's obviously intimately related to "democratic peace theory". People have tranced the idea of "capitalist peace" all the way back to Kant. In his essay, "Perpetual Peace", he argued that "the spirit of commerce" is "incompatible with war".

This particularly formulation, "No two countries that both had McDonald's had fought a war against each other since teach got its McDonald's" is from journalist Thomas Friedman's book The Lexus and the Olive Tree. It's not about that McDonald's specifically would act as a lobby, but rather McDonald's is a stand-in for all trade, economic globalization, etc. If you want to get fancy about it, McDonald's in this formulation is a synecdoche, a figure of speech where a part stands in for the whole.

Friedman's causal story is actually about the actions of individuals rather than firms. When he originally put forward his formulation of the theory in 1996, he said people in "McDonald's countries" "dont like to fight wars. They like to wait in line for burgers." That's not how most political scientists see democratic peace. After all, people in "McDonald's countries" are quite willing to go to war with non-"McDonald's countries". Most political scientists explain it as economic pressures, rather than pressures from citizens, in a globalized world help prevent (though don't completely prevent) conflicts.

By 2005, Friedman was saying that his McDonald's theory was at least partly "tongue-in-cheek" and I believe acknowledged counter examples, like Panama. He updated it with his (equally tongue-in-cheek) "Dell Theory of Conflict Prevention" in his book the World is Flat. Here, he seems more in line with political scientists seeing it as the behavior of firms rather than citizens that matter and says, "The Dell Theory stipulates: No two countries that are both part of a major global supply chain, like Dell's, will ever fight a war against each other as long as they are both part of the same global supply." This formulation leaves the door open for conflict in states that are peripheral to the global economy, like Panama (invaded by the U.S. in 1989), Lebanon (Israel and Lebanon fought a war in 2006, though it was Israel and Hezbollah, not Israel and the Lebanese army fighting), and maybe various recent Russian wars in its "near abroad" that are within the 20-year rule. It's unclear how India and Pakistan's conflicts, like the Kargil War in 1999, fit in. Maybe the fact it was a limited conflict, in Kashmir only rather than across all front, is a sign of the strength of the theory, but Democratic Peace and MAD theories of nuclear warfare also apply.

So McDonald's is a stand-in for, and a convenient measure of, the globalized World Economy. Don't expect McDonald's to do anything specific, but rather the weight of all the firms (in a mismatched case like this one, particularly in the weaker country) to push for a solution other than fighting that would disrupt global trade. One last thing I will add is why McDonald's? I think here Friedman is deeply influenced by a 1995 book called Jihad vs. McWorld by actual political scientist Benjamin Barber, based on an earlier article in the Atlantic (then still known as the the Atlantic Monthly). This wasn't so much about international relations, but local cultures in a global economy. McWorld stood in for globalization, cosmopolitanism, and firms' influence on culture and political process, and Jihad stood in for traditional values, parochialism, and strong local identities like nationalism or religious orthodoxy. (Barber's point, interestingly, was that neither McWorld nor Jihad actually promotes democracy, and that for a stronger democratic tradition we need to look elsewhere.)

Another book that likely influenced Friedman's choice of McDonald's was sociologist George Ritzer's 1993 The McDonaldization of Society. Here, Ritzer argues that society is being overwhelmed by extreme rationalization, systemization, and calculability (this relates to classical sociological theories of Max Weber) and that McDonald's was a symptom of growing cultural homogeny. Ritzer's argument was that this McDonaldization relied on four things: efficiency (over individuality), calculability (over quality), predictability (over uniqueness), and control (over autonomy). He argued that corporate forces like McDonald's were pushing rationalization/systemization into new realms, like personal interaction, creating an increasingly global homogeneity.

Friedman's book where his "Golden Arches Theory of Conflict" gets formulated, The Lexus and the Olive Tree, can really be seen as an attempt to put those two books together in some way. The Lexus stands for global economic development, prosperity, and unity, and the olive tree stands for traditional identities and customs.

McDonald's in all these cases (Friedman, Barber, Ritzer) stands in for economic globalization more generally. It's just an easy thing to point to, especially in the 1990's when these men were writing and McDonald's was growing rapidly, especially worldwide. The point wasn't that McDonald's specifically would act. As you see from the Friedman example, as we get further from the 1990's, you might point to other firms to be your stand-in for the degree of integration of the local economy with the world economy. For what it's worth, even if we accept Panama as a failure of Friedman's tongue-in-cheek formulation, the case for capitalist peace, while not perfect, is still pretty strong, as is the case for democratic peace, especially if you're willing to say "greatly reduce" instead of "entirely prevent". A NATO bombing campaign in Serbia broke out almost immediately after the book was published (there was more than one McDonald's in Belgrade at the time). In the second edition of the book, published only a year after the first, Friedman argued that the war ended quickly because Serbia didn't want to lose out on the benefits of the global economy (others, of course, make other arguments for why the war ended quickly, mostly involving Russia's influence in Serbian foreign policy, but that's beyond the scope of the 20-year rule).

Hey there, so I think you've maybe misunderstood what the "Golden Arches" theory is really all about.

At its heart, Thomas Friedman's "Golden Arches" theory is essentially a variation of capitalist peace theory, which (simple explanation) posits that two sufficiently economically developed and interconnected countries will not go to war with one another. This is often used to back up a theory of international relations known as democratic peace theory, which states that two democracies (based on certain criteria/definitions) are highly unlikely to engage in conflict with one another. Stuart Bremer, a peace and conflict studies professor, first connected the two saying that capitalist/economic peace theory actually had more explanatory power for lack of conflict between certain countries than whether or not they were democratic. Anyway, back to Friedman's theory.

When he lays out the "Golden Arches" theory in The Lexus and The Olive Tree, Friedman is essentially using McDonald's as a marker for a certain level of economic development and interconnectivity that would prevent countries with that same level of development/interconnectivity from fighting one another, i.e. McDonald's indicates that a country is at the point of economic development where capitalist peace theory becomes applicable. Friedman does not argue that McDonald's as a corporation has any agency in preventing war and maintaining peace. McDonald's, while arguably a reliable food choice in strange climes, is not the United Nations of fast foods restaurants and does not take any sort of active role within the context of stopping two countries from fighting, especially in Friedman's (relatively flawed but we're not really here to discuss that) theory. As such, the answer to your question is that McDonald's didn't do anything to mitigate the conflict and corporate management was not involved at all in the conflict outside of perhaps some basic acknowledgement of what stores were being forced to close.

As far as how they as a corporation handled it, I'm afraid I couldn't really tell you. I doubt even McDonald's itself really has an answer for you outside of the fact that they're one of the largest fast food companies in the world and they could probably suffer through the short term shutdown of a handful of restaurants (one other poster cited them as being a tiny percentage of all McDonald's) in one particular country.

The Lexus and the Olive Tree by Thomas Friedman

Dangerous Dyads article by Stuart Bremer

Was the operation named Just Cause as in, 'a just thing to fight for' or was it more 'Just Because?'

didn't Iraq have a McD's atleast after the Gulf war?