Before the mid-twentieth century, conquest of territory, and hence revision of borders by force was legitimate. Conquest and annexation had been a normal feature of all civilizations for millennia.
But in the mid-twentieth century, culminating in the UN Charter, all this changed. Acquisition of territory by force, and any violation of borders, was ruled out.
So, has this grand experiment been a success?
It has. It’s part and parcel of a growing aversion to warfare and violence more generally, led by the liberal West. Mostly a consequence of growing war aversion, I am willing to concede it has been probably a minor cause of war decline too.
But, does it have any downside?
First, the rule was brought in against conquest, but now that is not much of an issue. More important are civil wars. For civil wars, it brings bias against separation, which can often be the best remedy to a civil war. It makes separation harder.
Second, Boaz Atzili argues it may lead to civil wars by perpetuating weak states. There’s an old idea that war makes strong states, Attali adds that strong states prevent civil wars.
Interesting idea, but I’m not quite convinced.
Ending the rule would not be a remedy for today’s weak and failed states. If Ethiopia and Kenya were allowed to conquer Somalia would we then have an effectively governed state in the Horn? Would it have an efficient civil service, a competent government. Would it be a Singapore or a Denmark of probity and expertise in governance? I doubt it. We would have a couple of bigger states, but they would not thereby become effective states.
In short, effective governance arises from sources other than threat of conquest.
Reference: Boaz Atzili, Good Fences, Bad Neighbors: Border Fixity and International Conflict (Chicago: The University of Chicago Press, 2012).