North Korea: There Is No Such Thing As Stable Deterrence

The overwhelming consensus in the U.S. foreign policy community is that a nuclear-capable North Korea is perfectly acceptable since North Korea can simply be deterred. As Vipin Narang and Ankit Panda put it in their analysis of the Singapore summit’s failure to bring about North Korean denuclearization, "the significant silver lining is that [the Singapore summit] could lead to a stable deterrence relationship between the two countries." 

Let me begin by noting that financial deterrence worked (in a fashion): the fact that a financial crisis is bad for bankers meant that the financial crisis wasn't caused by 17 financiers waking up in New York one morning and randomly deciding to wreck the global financial system. The crisis happened regardless because individually rational decisions that made sense to the people who took them at the time interacted in ways that exposed the financial system as a whole to the risk of a catastrophic failure (systemic risk). If systemic risk is high and if you play financial crisis roulette for long enough, you lose. 

So, in the absence of CVID, the U.S. will be forced to play deterrence roulette with North Korea. Just how risky would that be?  

As the long history of financial crises demonstrates, this question isn't about the risk that Kim acts irrationally (nobody thinks that Kim is going to wake up one morning and randomly decide to nuke Los Angeles). The question comes down to this: how much risk is built into the system when everyone behaves rationally? And here the evidence indicates that any deterrence arrangement between the U.S. and North Korea will inevitably be subject to an enormous amount of systemic risk. In this situation, it would be exceedingly rash to bet that the U.S. will never lose a round of deterrence roulette.

North Korea seeks to obtain nuclear weapons to prevail against the U.S. if the U.S. acts to prevent North Korea from achieving objectives that harm the U.S. and/or its allies (a nuclear crisis episode). As Matthew Kroenig's new analysis of nuclear strategy shows, countries rationally seek to prevail in these situations by acting to increase the probability of a nuclear exchange. As this probability ratchets up, each country weighs the expected consequences to them of a nuclear exchange against the importance of their objectives. Eventually, as the risk of a nuclear exchange increases, one country throws in the towel and the other one wins. Alternatively, a nuclear war happens. 

History shows that crisis episodes have come very close to ending in nuclear war. During the Cuban Missile Crisis, for example, the captain of a Soviet sub came under the mistaken impression that he was being attacked by the U.S. and would soon be sunk. He seriously contemplated using a nuclear-armed torpedo to destroy a U.S. aircraft carrier first (he was talked out of doing so by other senior officers on board). Given that the U.S. military was on a hair-trigger alert at the height of the crisis, any Soviet attack that killed thousands of Americans–let alone one with nuclear weapons–would surely have led to war. Reflecting upon the crisis, Graham Allison wrote that "Kennedy thought the chance of escalation to war was 'between 1 in 3 and even', and what we have learned in later decades has done nothing to lengthen those odds". 

Even without the protection that nuclear weapons provide, North Korea has attacked U.S. military assets, raided Japan and kidnapped Japanese citizens, sunk a South Korean ship, shelled South Korean territory, bombed a South Korean passenger jet, provided military assistance to hostile powers, and engaged in extensive cyberwar operations against the U.S. and its allies. Given this track record, North Korea will almost certainly act in a way that provokes a crisis in the future.  

Still, one may think that even a 33% chance of war at some point in the future is a much better bet than a 100% chance of a preventive war now to eliminate that risk. And that would indeed be the case if North Korea in the future would be no more powerful than North Korea is today. Unfortunately, North Korea's nuclear program is advancing rapidly. The yield on North Korea's nuclear weapons has increased from around 10 kt in 2013 to around 250 kt in 2017, and North Korea is now perfecting its ability to mount these much more powerful weapons on missiles capable of striking the U.S.. Furthermore, Kim vowed earlier this year to "mass produce nuclear warheads and ballistic missiles." Consequently, it would be worth a preventive war with a far weaker North Korea now to eliminate a significant risk of a nuclear exchange later.  

A crisis that spins out of control is only one–and perhaps not the most dangerous–pathway to nuclear war. In a deterrence arrangement between two hostile countries (say N and U), each country will logically, rationally, and sensibly put into place a second strike capability so as to deter an attack by the other. But these logical, sensible, and rational actions designed to prevent a deliberate attack inevitably create the risk of an accidental nuclear war. 

If N rationally commits to launching a retaliatory strike on U given a true alarm that U is attacking (or is about to attack), then there is necessarily a chance that N launches a first strike on U by mistake in response to a false alarm that U is attacking. Obviously, U cannot deter N from launching what N mistakenly thinks is a retaliatory strike because launching a retaliatory strike when under attack is precisely what deterrence is all about.  In a sense, accidental nuclear war is the autoimmune disease of nuclear deterrence.

The risk of an accidental nuclear war is real and substantial. In what may be the most famous (but by no means the only) nuclear war near miss, Soviet early warning systems detected (with the highest level of reliability) the launch of a U.S. first strike on 26 September 1983. The early warning duty officer had standing orders to report such an attack to senior military and political officials. Given the reliability of the signal and the extreme fear of a U.S. first strike by the most senior levels of Soviet leadership at the time, it is likely that, if the alarm had been reported, the Soviets would indeed have retaliated (by mistake). Fortunately, the duty officer on the spot was Stanislav Petrov. He deliberately ignored his orders to report the alarm up the chain of command. Instead, he went with his gut instinct and classified the incident as a false alarm before knowing that it was, in fact, a false alarm.

Now, one may think that–given the disastrous consequences of a nuclear exchange–everyone in a nuclear command chain will always act as Stanislav Petrov did. Stanislav Petrov himself did not agree with this view. Reflecting upon the incident in a BBC interview, he thought that there was only a 50/50 chance that even he acted as he did instead of reporting the alarm up the chain. He also thought that, if any of the other duty officers had been on the crucial shift, they would definitely have reported the alarm up the chain. History suggests that Petrov is correct. 

In 1995 a Norwegian satellite launch appeared to the Russians to be a missile launch by a U.S. submarine. The duty officer on the spot did report the alarm up the chain of command. Russian nuclear forces went onto heightened alert, and President Yeltsin had to decide whether or not to retaliate. Fortunately for the world, Yeltsin was not as paranoid as Andropov was in 1983, so he chose not to retaliate (by mistake). But, in slightly different circumstances, either the 1983 near miss or the 1995 near miss could have resulted in a U.S.-Russian nuclear war.

As informative as this case study evidence is, a more rigorous statistical examination of accidental nuclear war risk would be extremely valuable. However, as one might expect, there is only very limited publicly available data on nuclear early warning system effectiveness and performance. Using the data there is, Barrett, Baum, and Hostetler put the chance of an accidental U.S./Soviet nuclear war at 2% per year (mean estimate). If the chance of a U.S.-North Korean nuclear war is also 2% per year (and it could be higher), then there is about a 45% chance of a U.S.-North Korean nuclear exchange at some point over the next 30 years (Kim is in his mid-30s).   

Deterrence is in part about putting into place a second strike capability to eliminate your rational opponent's incentive to launch a first strike. But deterrence is also a submarine captain, mentally and physically exhausted from attempting to dodge detection by the enemy navy, breathing bad air, thinking that his sub is about to be destroyed, and deciding whether or not to take some of the enemy with him before that happens. Deterrence is an early warning duty officer seeing a "Launch" alarm on his screen, feeling like he is sitting on a hot frying pan, and deciding whether to disobey his orders or to report what his gut is telling him is a false alarm up the chain of command (in North Korea disobeying orders in such circumstances could lead to torture and death). Deterrence is a leader being woken up at 3 am with the news that early warning systems have detected with high reliability the launch of a decapitation strike, and having a few minutes to decide how to respond. The cold serene logic of game theory offers no guarantees against a catastrophic deterrence failure here. 

In practice, then, choosing to deal with the North Korean nuclear threat by deterring them rather than by CVID is to take a leap of faith–a bet that somehow, in some mysterious way, things will always work out for the best. The crisis won't spin out of control. The early warning systems will always work perfectly, or, if they don't, a Stanislav Petrov will be there to save the day. Studies of nuclear crisis episodes, the case study evidence on nuclear war near misses, and the statistical evidence we have on accidental nuclear war risk all suggest otherwise. The risk of a catastrophic deterrence failure is inevitably real and substantial. Or, in other words, there is no such thing as stable nuclear deterrence.  

The awful arithmetic our situation is that a preventive war now–as horrible as that would undoubtedly be–is a much more prudent option than a reckless gamble on never losing a round of deterrence roulette (where losing means a nuclear exchange with a vastly more powerful North Korea in the future). Every day that the U.S. delays acting makes the preventive war that it will need to wage more costly. As John von Neumann put it, "If you say why not bomb them tomorrow, I say why not today? If you say today at 5 o'clock, I say why not 1 o'clock?".

President Trump needs to present North Korea with a final opportunity to comply with the Singapore summit agreement by taking concrete steps to begin the CVID process. If North Korea declines, he must summon up his inner Lincoln, find his General Grant, and get it done. 

Kevin R. James is an economist in the Systemic Risk Centre at the London School of Economics.