Pyongyang knows there is no way to use their weapons for gain that would not immediately provoke massive counter-costs.
Striking North Korea would be incredibly risky, and the United States has learned to live with other states’ nuclear missilization. Russia, China and Pakistan are powers whom Washington would almost certainly prefer were not nuclear. Yet the United States has adjusted. Each of those three, including Pakistan, has treated its weapons reasonably carefully. There has not been the much-feared accidental launch or hand-off to terrorist groups. All appear to think of their nuclear weapons as defensive and for deterrence purposes. Indeed, the offensive potential of nuclear weapons is curiously constrained. They would so devastate an enemy that conquest of said enemy would be pointless—who wants to take-over an irradiated wasteland? Plus, nuclear use would likely bring nuclear retaliation on the attacker, in which case any benefit of a war would be lost to the huge costs of nuclear destruction in the homeland.
This logic seems to apply to North Korea as well. In the most extreme possible scenario, where Pyongyang used nuclear weapons against Seoul to facilitate a successful invasion, the devastation in the South would be so awful, that one wonders why North Korea would want to invade at all. Due to the peninsula’s mountainous terrain, only a few areas of South Korea are easily habitable for large numbers of people. Nearly 75 percent of the population lives on 30 percent of the landmass. Those small areas—basically the South biggest cities—would be targets of Northern nuclear weapons in any such war. If North Korea were to win that conflict, it would then inherit those irradiated, blasted population zones, in addition to scarcely usable mountains. What would be the point of winning then? Of fighting at all?
Similarly, North Korean nuclear use against the South—or Japan or the United States—would lead to devastating American nuclear retaliation. South Korea and Japan have been treaty allies of the United States for decades. These relationships are about as robust as any in the U.S. alliance network. Countless secretaries of state and defense have pledged to protect Seoul and Tokyo. So American nuclear retaliation would almost certainly follow any Northern offensive nuclear strike. North Korea would inherit an apocalyptic wasteland in the South, while absorbing punishing nuclear retaliation at home—so punishing in fact, that the regime itself might collapse under the weight of the social chaos unleashed by American nuclear strikes.
And if that were not bad enough, one could easily imagine China attacking North Korea if Pyongyang offensively used nuclear weapons. China may tolerate North Korea’s nuclearization, but it is hard to imagine Beijing tolerating North Korea using such weapons to start a war. Beijing knows that China may well could be the next target. It is easy to foresee the United States and China working together to destroy North Korea if it aggressively used nuclear weapons.
Some fear North Korea might ‘hand off’ a weapon to rogue groups, but no states have done this yet. Others suggest nuclear weapons might be a method to bully South Korea into subservience or permanent subsidization. But so long as South Korea remains allied to the United States, it is not clear why North Korean nuclear blackmail would succeed. Pyongyang’s nuclear weapons level the playing field in the peninsula rather than shift it against South Korea.
In short, North Korea’s possible use of its nuclear arsenal is highly constrained. It fits the profile of other state’s nuclear weapons—great as an ultimate guarantee of national defense and sovereignty, great for national prestige, but hugely risky for the offense. It is not clear that North Korea can escape the issue of practical use which so many other nuclear powers have tried to solve. There is simply no way to use these weapons for gain that would not immediately provoke massive counter-costs.