My (high school) history teacher made some comments today about what he termed "the security dilemma"; that when one country successfully invades another, they are forced to ramp up defense spending in order to maintain their hold. As a result, the invading country feels like their military is in a good position to invade the next country/territory. And from there, they go through a cycle of invasion and increased spending, until they put a stop to the invasion or collapse. Is this an arguable historical position to take? For some reason, I have trouble believing that it is a widespread pattern, and pointed out the United States as an example of when a country acquired territory without falling into the "security dilemma." However, he argued that the settler-colonialist nature of the US made it unique, and mentioned that defense spending did actually increase significantly as Americans expanded westward.
The bigger question I had, though, was whether collapse inevitably follows from invasion. During a discussion of current events, a classmate asked, "When Russia loses, what will happen?" I said that saying Russia would lose was quite the assumption to make, but my history teacher made a comment along the lines of "Countries that invade other countries never last, which makes Russia's collapse inevitable. You should ask [classmate] about the life cycle of an empire sometime."
This generalization really bothered me. Can it really be true that there's no such thing as a long-term successful invasion?
Disclaimer that I’m not a trained politician scientist, so if anybody like that appears and starts contradicting me they’re probably right. But I don’t think your history teacher knows what the security dilemma is.
In the realist school of international relations, the security dilemma is used to refer to the problem that any given actor increasing its own security actively decreases the security of other actors in your system. But what does that mean in more concrete terms? And why is that a problem?
Well, let’s look at it this way. You’re the leader of a nomadic tribe that’s called, let’s say, the Confederation. And you live next to a settled empire called the Sultanate. One day you realize that your ancestral spears need a fresh coat of paint to better defend your loved ones, so you decide to hire some blacksmiths to reforge them. So you do so, and your friends and family are very impressed with your wise leadership. After all, better defenses are always a good thing, right?
But then, to your south, the Sultanate sees that. And what, their Sultana wonders, scratching at her chin, could you be doing with those polearms? Certainly not LARPing. So she has a few more borderland fortresses, just in case you decide to pop in for an involuntary visit.
Really, raiding your settled neighbors is the last thing on your mind at the moment. But still, you see the looming walls being built at the boundary between your two peoples, and come to the rather logical conclusion that the Sultana intends to launch a military invasion and worried about retaliation, has carefully placed all those garrisons between her shiny new capital and you.
Of course, you could just ask her what’s up with all those forts. But when the Sultana tells you that she’s only building those because she sees you forging all those fancy new spears, and that she’d gladly tear down her forts if you sold her all of those, then how do you know to trust her? What if she’s just softening you up for that invasion?
This is the essence of the security dilemma. When actors don’t trust each other, it often leads to arms races like these where any action to make one entity safer makes the rest of the entities less safe (note- I considerably simplified it to only two actors in my example, most of the time this is used for way more than that). A sort of “prisoner’s dilemma” on a geopolitical level, as Azar Gat put it. Sure, you didn’t reforge your weapons for an invasion and neither did your Sultanate counterpart build her forts to attack you, but how do you know that? How does she know that?
There are two ways to get around this. First, you could just actually launch that hypothetical invasion, and now you don’t have to worry about your pesky neighbor. But how do your other neighbors feel now that you’ve proven yourself to be a savage warmonger? Eliminating other actors is just another action that the security dilemma has accounted for. The other option, however, is what most societies in human history have to some extent gone with: building more trust. Marriages, feasts, diplomatic visits, gifts, all that help you reinforce the notion that yes, your reforged polearms are for defense alone, and not attacking your neighbor. But… humans haven’t ever had the best track record for doing that.
So in essence, your teacher is wrong. I honestly have no idea what they’re trying to talk about, but it’s not the security dilemma, at least not in the academic sense.
Sources
Azar Gat, War in Human Civilization (pages 97-100)