Bigger isn’t always better: Why the US fails to deter North Korea, despite nuclear superiority

A hefty, 60-ton missile that North Korean leader Kim Jong-un has fondly called his “most powerful nuclear weapon” featured heavily in this year’s Victory Day parade held on July 28 in Pyongyang. The missiles are North Korea’s most sophisticated military technology. Capable of carrying nuclear weapons, the missiles boast an estimated maximum range of 15,000 kilometers—enough to hit targets anywhere in the United States.

Since last year’s parade, North Korea has tested dozens of these ballistic missiles, more than it ever has in a single year. Although North Korea continues to build up its nuclear capabilities, its arsenal of just dozens of weapons is minuscule compared to the US arsenal of thousands. So, why has the United States proven unable to deter North Korea from testing?

The answer to this question is two-fold. First, the United States lacks the leverage needed to effectively influence North Korea through economic means. Second, US nuclear superiority over North Korea paradoxically makes Kim consider his nuclear arsenal essential to the survival of the regime. North Korea must make sure to stand strong in the face of each new crisis, lest it looks vulnerable. It’s this unbending resolve that makes North Korea effective at resisting the demands of its much more powerful adversaries.

Without Russia and China. North Korea’s recent parade commemorated the 70^th anniversary of the July 27, 1953 armistice agreement of the Korean War. That war saw North Korean forces fighting alongside the Soviet and Chinese militaries against South Korea and the United Nations Command, led by the United States. It was fitting, then, that this year’s parade featured visits by Russian and Chinese officials, in the first such visits since the COVID-19 pandemic. The presence of these foreign dignitaries signified the strengthening relationships between North Korea and its neighboring allies.

North Korea is largely isolated on the international stage, in no small part due to very significant sanctions that limit the regime’s ability to trade across the world. The country’s largest trading partner is China. North Korea is wholly dependent on trade with—and aid—from Beijing.

Although there is less trade between North Korea and Russia, North Korea imports significant amounts of food and oil from its northern neighbor. Trade relations have also recently warmed between North Korea and Russia. Pyongyang has reportedly exported arms and artillery to Moscow to support Russia’s war effort in Ukraine, and the two partners have restarted train travel along the Trans-Siberian Railway for the first time in years.

In comparison, the United States lacks economic leverage: Heavy sanctions have prevented any ties between the two countries and forced North Korea to adapt to non-reliance on the United States and its allies. Although the United States has, at times, provided emergency aid to North Korea, the largest sources of food aid to the country come from South Korea and China. The regime seems largely resilient to this trend, even shunning foreign aid—including vaccines—throughout the COVID-19 pandemic. In fact, over time, aid coming to North Korea from countries other than South Korea and China has slowed.

Recently, Russia and China have been instrumental in sheltering North Korea’s growing provocations, but they have not always been so accommodating of the North Korean nuclear program. Nine UN resolutions—each with approval from Moscow and Beijing—have been passed condemning North Korean nuclear and missile testing. Each resolution also calls upon Pyongyang to suspend these illicit activities, although little lasting progress has been achieved to this end. The last UN resolutions on the issue of the North Korean nuclear program were passed in 2017 and there are few signs of any new UN activity in that regard. Russia and China have resisted any additional steps, despite repeated calls for the UN to discuss North Korea’s recent testing uptick.

Russia and China have also previously been involved in the “Six Party Talks,” a series of negotiations intended to halt the North Korean nuclear program. The last talks were held in 2008, with North Korea declaring in 2009 that it would no longer participate. Although China last called for the talks to be renewed in 2017, there is little hope that they will resume, at least in the short term.

While Russia and China have resisted condemning North Korea for its recent missile testing, the United States, Australia, Japan, South Korea, and the European Union have imposed additional, unilateral sanctions on North Korea and demanded that the tests cease. But despite these efforts, North Korea has continued to launch.

The role of resolve. If the United States is unable to use economic sticks to prod North Korea, what about military ones? My colleague Abby Fanlo and I published new research last month in Security Studies, which suggests that it is not despite nuclear superiority but because of it that the United States struggles to deter a comparatively much weaker adversary. That is, the asymmetry between the two countries’ nuclear forces can be considered a key obstacle to North Korean denuclearization. The study, which examines all the nuclear crises that occurred until 2010, shows that carrying a big stick—or, at least, having a bigger nuclear button than one’s enemy—can unfavorably change the dynamics of a crisis.

Crises that emerge between nuclear-armed countries with vastly different capabilities consistently represent high-stakes scenarios for the less-powerful adversary. Consider the Korean War, during which the Soviet Union wanted to maintain vital access to neighboring territory. Although the US nuclear arsenal was substantially larger at the time, Soviet nuclear threats effectively dissuaded the United States from escalating the conflict.

Asymmetric crises tend to be high stakes because of a selection effect. After all, it makes far more sense to acquiesce to the demand of an adversary that is many times more powerful, unless those demands would put your core interests at risk. This dynamic, though, doesn’t work the same way when a set of adversaries is equally matched.

When two countries with very similar nuclear capabilities face off in crises, the principle of mutually assured destruction is at work. In these so-called “symmetric” crises, both sides can impose equal consequences on the other if a crisis escalates. As a result, they possess general deterrence, which enables them to prevent their adversaries from putting pressure on their most serious interests. This logic underlies why the Cold War was “cold.”

In asymmetric crises, however, the weaker nuclear power is caught between a rock and a hard place. It can resist its adversary’s demands and risk a crisis escalating into a war. Often, though, giving in to those demands is off the table. The weaker country then has few options but to show its resolve to fight in a bid to secure immediate deterrence and fend off its adversary—albeit temporarily. In other words, the weaker country persists, because it has nothing more to lose; it is already committed to the maximum or bust.

And research shows that this strategy works. When a country has over 50 times more nuclear weapons than its adversary, its chances of emerging victorious from a crisis are nearly zero. If it has any more than three times as many nuclear weapons as an adversary, it will lose crises more often than it wins. Using novel methodological approaches designed for small datasets, the new research shows that there is no statistically significant advantage to exceeding one’s adversary’s nuclear arsenal by more than half its size.

The crucial commitment problem. These dynamics play out clearly in the US-North Korea relationship. At the core of the crisis between the United States and North Korea is a commitment problem, one involving tensions over the future of both the North Korean nuclear program and the authoritarian regime that has championed it. For its part, the United States would like to be rid of both. US leaders have repeatedly made it clear that a nuclear-armed North Korean regime will not be accepted.

President Joe Biden’s 2022 National Defense Strategy states that “there is no scenario in which the Kim regime could employ nuclear weapons and survive.” Former Central Intelligence Agency director Mike Pompeo stated that President Donald Trump had ordered the agency to “separate the North Korean regime from its missiles and nuclear weapons.” President Barack Obama explained in a 2015 interview that the Kim regime was “brutal and … oppressive … you will see a regime like this collapse … and that’s something we are constantly looking for ways to accelerate.”

The United States could, in theory, say it would agree to a deal that reduced or removed the North Korean nuclear program in exchange for allowing the regime to stay in place. But over time, the United States would be unable to commit to keeping that promise. It would have every incentive to take advantage of the diminished North Korean capabilities to impose regime change on Pyongyang. (After all, the United States pursued regime change in Libya after its disarmament deal.) As Stanford University professor James Fearon writes, the real problem is that North Korea “can’t trust us.” So, they cannot—and will not—commit to disarm.

As a result, when crises emerge between the United States and North Korea, the fate of the North Korean regime is at stake—and, for Kim, it doesn’t get more high-stakes than that. Pyongyang must then show its resolve in the face of any threats to its nuclear program. For North Korea, backing down to such threats is an existential concern, even if bidding up the risk of a nuclear conflict could also have existential consequences. In these high-stakes settings, North Korea has a risky advantage.

Despite having a comparative strategic advantage, the consequences of North Korean nuclear escalation are far too great for the United States to bear. As a result, North Korean signals of resolve are credible, and they are often sufficient for immediate deterrence, despite the regime’s limited nuclear capabilities. That leaves the United States at a distinct disadvantage. It’s time the United States learned that, at least in this situation, being bigger isn’t always better.

US officials should think twice before adopting any measures meant to expand US nuclear capabilities. Such a policy is unlikely to be helpful when the United States faces far weaker adversaries, like North Korea. If Pyongyang’s resolve is indeed its key advantage, the United States should work to undermine and counterbalance that—not by building up capabilities, but by showing cohesion and determination. The newly announced coordination efforts between US, South Korean, and Japanese forces represent a step in the right direction, although continued synchronization will be critical to cement trilateral ties.

The United States can’t simply demand that North Korea stops its provocations. But it can handle each such provocations with care, responding with coordinated, confident messaging that makes it clear North Korea is not the only actor with much at stake.