As the possibility of conflict with North Korea sharpens in 2018, there has been much discussion of North Korea’s ultimate aims. I have argued that it is highly unlikely that North Korea actually wants to absorb South Korea—or more specifically, that North Korea is prepared to carry any serious costs in order to pursue that goal. But there is a continuing, very hawkish interpretation that North Korea really does seeks final unification, so it is worth gaming out how that might happen—and why absorbing South Korea would likely overwhelm North Korea.

The ultras’ interpretation takes seriously what North Korea says. And indeed, North Korean elites routinely pronounce their interest in unification. Kim Jong-un mentioned this topic around a dozen times in his New Year’s address. Yet this has never struck me as serious “evidence” of North Korean goals.

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First, South Korean elites say this all the time too. That both sides of an artificially divided nation would seek unity is hardly a surprise. Yet no one talks about South Korea recklessly pursuing unification and risking regional stability for that goal. So why is North Korean rhetoric, from a state which routinely lies, taken so seriously? And if we believe them when they talk of unity, then why not believe them when they say that their nuclear weapons are intended for deterrence and defense?

Second, talk is cheap. The two Koreas are locked in a zero-sum contest over national legitimacy. Both want to speak for the minjok (the Korean race), so both claim unification as their goal. This is written into their constitutions, and their elites evince that goal routinely in their public commentary. Naturally then, they will both talk about unification a lot. But the acid test is whether each side is carrying any real costs for that outcome. Are they engaging in what social science calls “costly signaling” or taking serious chances that put their regimes at risk to pursue this goal? Is North Korea, for example, building up offensive weapons that would allow it to overrun a South Korea abandoned by the United States? And no, nuclear weapons are not evidence of such signaling, as the primary utility of a nuclear weapon is defensive.

Third, the North Koreans lie relentlessly. Rhetoric is easy, especially for North Korea. It should be very obvious at this point that the North Koreans will say anything, so why is their talk given much credence? If there was ever a country where we should look at what they do, not what they say, it is North Korea. And there is little evidence that North Korea is planning some kind of serious unification bid.

In short, is North Korea actually carrying real costs and risks to pursue the goal of coerced unification? Talk supporting that goal is not really evidence, besides which there is no obvious Mein Kampf-style text which lays out some grand, forceful unification plan. (No, this is not it.) Sure, all other things being equal, the North would like to control the South. In the fever dreams of the Kims, they presumably lead the Koreas together into a promised land of unity and socialism. But maximal hopes are not really evidence. The ideal preferences of the North Korean elite hardly suggest that they will act on them. Instead, as always, North Korean elite behavior suggests that they: are dead set on survival and want to enjoy a gangsterish good life.

Even if all this is incorrect, consider just how difficult coerced unification would be:

(A) The U.S. alliance with South Korea would have to collapse.

No North Korean military action against the South could take place as long as the South remains allied to the United States. That alliance is almost seventy years old. It has endured all sorts of ups and downs in the past. Sure, all other things being equal, the North would like it ended, but again, are they carrying any real costs to pursue that goal? That the North wants the United States out is not in itself evidence that it will take real risks for that end. No North Korean leader since the 1970s has actually considered the use of force against the Americans in South Korea.

(B) South Korea would have to be defeated on the battlefield.

Per the ultras, assume that the United States was pushed out (decoupling). A coerced, Northern-led unification would still have to overcome the South Korean military. Yet it is widely understood that the South Korean military is a vastly better fighting force: better trained, with far greater resources, in better health, with far superior technology, less corrupt, better lead, and so on. The South Korean defense budget is expanding and will soon be the size of North Korea’s entire economy. South Korea’s population is more than twice North Korea’s, and its GDP is almost forty times the size of North Korea’s GDP. This is surely not a fair fight. Without the United States, the fight would be harder, but in ten years of going to conferences in South Korea, I have never heard anyone say that North Korea would win a conventional inter-Korean conflict. The use of nuclear weapons might change the battlefield characteristics, but that obviates the point of winning—who wants to conquer irradiated blast zones in widespread social chaos? The point is to take South Korea reasonably intact, otherwise it is yet another burden.

(C) Occupying South Korea would be a catastrophe for the North.

Per the ultras, assume yet further, that the North somehow won anyway. The war would practically bankrupt it, and its occupation of the South would be far more like American post–Civil War Reconstruction—with massive social resistance leading the occupier to basically give up out of exhaustion after awhile—than the peaceful absorption of German unification in 1990. If nukes were used to win, then the occupation would be that much worse; can anyone imagine the North Korean military operating sustainably in an irradiated occupation environment? It gets worse:

North Korea would immediately cut off South Korea from the global economy, which would promptly impoverish it. The wealth the North wants from the South requires the South’s connection to globalization, which the North could not tolerate.

South Korean citizens, accustomed for decades to the freedoms of liberal democracy, would resist. Given the huge size of the South’s population compared to the North Korean military, the occupation force would be overwhelmed. There would be guerilla actions everywhere.

The cost of occupying a hostile population would be staggering, especially for an economy as small as the North’s, which had just been badly stressed by the war. Looting South Korea might pay for that briefly, but that would not be sustainable, and it would make the medium-term problem of subduing and integrating South Korea even more difficult.

The North Korean military is not trained at all for what the U.S. military calls “phase IV” operations—counterinsurgency, occupation, transition and so on. If you thought the U.S. military botched this effort in Iraq, try to imagine it from a badly trained, corrupt, under-funded totalitarian military.

The blowback into North Korea itself from all this would be massively destabilizing too. North Korea is highly stylized society with very unique, highly refined rules, most obviously the songbun system. The North is very rigid, and not designed at all for integrating outsiders or immigrants. Grafting its framework onto fifty-three million resentful people would be a nearly impossible task and almost certainly overwhelm the corrupt, rickety, dysfunctional administration in Pyongyang. North Korea soldiers in the South would come home with outlandish tales of Southern wealth. North Korean commanders in the South would be sorely tempted to freelance in this wealthy environment. Ideological indoctrination of all these conquered people would gargantuan task facing enormous resistance. The hugely complex administrative burden of managing the South would likely lead to state breakdown in the North.

The best analogies for such an administrative disaster and the massive pressures it would place on the occupier are U.S. reconstruction, or, as a contemporary example, the Israeli occupation of the West Bank. I cannot imagine the Northern leadership would be willing to take such risks.

Robert Kelly is an associate professor of international relations in the Department of Political Science at Pusan National University. More of his writing can be found at his website. He tweets at @Robert_E_Kelly.

Image: Uniformed women march past the stand with North Korean leader Kim Jong Un and other high ranking officials during a military parade marking the 105th birth anniversary of the country's founding father Kim Il Sung, in Pyongyang April 15, 2017. REUTERS/Damir Sagolj​