Can America Live With a Nuclear North Korea?

The lessons—and limits—of deterrence

AFP / KCNA via KNS / Getty / Katie Martin / The Atlantic

The Trump administration claims “all options are on the table” for dealing with North Korea’s nuclear-weapons program—from using military force, to pressuring China to punish its North Korean ally, to Donald Trump negotiating directly with Kim Jong Un. But what do those options look like? And what consequences could they have? This series explores these questions, option by option by option.

The Trump administration’s most striking statement on North Korea has come not from Donald Trump himself, with his talk of locked-and-loaded fire and fury, but from the president’s national-security adviser, H.R. McMaster. In an August interview with ABC, McMaster said something that received little attention relative to its import. He disagreed with the assessment of Susan Rice, his predecessor in the Obama administration, that the United States and its allies could, if need be, “tolerate nuclear weapons in North Korea” and “rely on traditional deterrence” to prevent the North from using them, just as they had deterred the Soviet Union from using its much more massive nuclear arsenal during the Cold War.

McMaster, who has a doctorate in military history, suggested that “classical deterrence theory” couldn’t be applied to a nuclear-armed North Korea because Kim Jong Un’s regime was different than other governments with nuclear weapons. It is ruthless, he argued, inflicting “unspeakable brutality against its own people” and its opponents, even killing off Kim’s half-brother with VX nerve agent smack in the middle of a Malaysian airport.

Maybe McMaster wasn’t articulating administration policy; other Trump advisers have hinted that deterrence can work with North Korea. But consider what it means if McMaster was. If North Korea can’t be deterred, then North Korea must be denied the world’s deadliest weapons—particularly, from the U.S. perspective, nukes that can target America—by any means necessary. Since we’re hurtling toward a time when North Korea will have these capabilities (if they don’t have them already), and since international efforts to coax and coerce North Korea off this course have so far failed, McMaster’s logic leads to some dark places.

As Colin Kahl, the former national-security adviser to Vice President Joe Biden, put it shortly after McMaster made his comments, if North Korea is undeterrable, and a North Korea capable of threatening the United States with nuclear weapons is thus intolerable, then war to prevent North Korea from posing that threat seems inevitable.

What Exactly Is Deterrence?

The concept of deterrence can be whittled down to a simple message, according to Mira Rapp-Hooper, an expert on Asian security issues at Yale University: “If you do X thing that I don’t like, I will do Y thing that will be even worse for you.” For deterrence to work, whoever is considering X must take seriously the threat of Y and be “rational” enough to fear it. If one country doesn’t fire nukes at another because its leaders believe the second country will respond with a devastating nuclear counterattack, then deterrence is operating as it should. Nuclear deterrence is a subset of general deterrence, which encompasses various methods of discouraging hostile actions.

“In the annals of international relations, there are [few] theories that have a better track record” than nuclear deterrence, Fred Kaplan writes in Slate. That track record, in brief: No conflict involving nuclear weapons in the 70-plus years since the U.S. bombings of Hiroshima and Nagasaki.

The subtext of McMaster’s remarks to ABC is that the Kim regime is so hostile and brutal that it isn’t rational enough to fear punishment. But McMaster hasn’t offered much evidence for that assessment. The United States and its allies, after all, have successfully deterred other hostile, brutal governments from using nuclear weapons, including Joseph Stalin’s in the Soviet Union and Mao Zedong’s in China. And if North Korea’s leaders are really irrational—if they don’t respond to incentives and disincentives as other leaders would—why is the Trump administration using economic sanctions and other forms of pressure to try and change their calculus on developing nuclear weapons? (The National Security Council did not respond to a request for comment from McMaster.)

Given that missile-defense systems are unreliable, the United States has for decades been practically “defenseless” against the nuclear-tipped long-range missiles possessed by Russia and China, Robert Gallucci, a former Clinton administration official who negotiated with the North Koreans in the 1990s, noted earlier this year. But it has relied on deterrence purchased with the strongest military in the world. The Trump administration, Gallucci wrote, should “disclose what exactly is new about the North Korean threat that makes deterrence suddenly unreliable. Certainly it is not the quality or quantity of North Korea’s nuclear weapons. At the height of the Cold War, the number of Soviet weapons … reached 30,000 or so. The North Koreans have less than 20.”

How North Korea Could Be Deterred

Just because deterrence has worked in the past to prevent nuclear attack does not mean that deterrence can halt a country’s nuclear development. Plenty of nuclear-armed powers have failed to prevent their rivals from getting nuclear weapons: the United States with the Soviet Union, the Soviet Union with China, China with India, India with Pakistan.

Deterrence is better thought of as a way to reckon with reality; North Korea has demonstrated ever more powerful nuclear bombs, missiles of increasing range, and potentially the capability to deliver those bombs via those missiles. It has demonstrated, in short, that it is already a rising nuclear-weapons power. And deterrence can be paired with efforts to alter this reality by containing North Korean provocations and constricting its nuclear arsenal, whether through negotiations, sanctions, or cyberattacks.

The United States could deter North Korean aggression by moving additional military assets, including missile defenses, to East Asia, according to Wallace Gregson, the assistant secretary of defense for Asian and Pacific security affairs in the Obama administration. The Trump administration, in fact, just finished installing the THAAD missile-defense system in South Korea. The U.S. could also return to a Cold War policy of deploying battlefield (“tactical”) nuclear weapons in South Korea, even though George Bush withdrew these arms in 1991 because they were considered unnecessary to defend South Korea. Doing so, Gregson said, could emphasize “that we’re determined to fully deter any [North Korean] attack and, should deterrence fail, that it would result in a prompt and overwhelming response.” Some, including Donald Trump as a presidential candidate, have gone so far as to suggest that Japan and South Korea acquire their own nuclear weapons.

Deterrence can also involve statements of America’s commitment to defend itself and its allies. Unlike Trump’s vow to unleash “fire and fury” in response to mere “threats” from North Korea, his message on Twitter that U.S. “military solutions” were “locked and loaded” should “North Korea act unwisely” was, as the former U.S. Defense Secretary William Perry told me, essentially a “crude way” of reaffirming America’s decades-old deterrence policy.

Jon Wolfsthal, who worked on nuclear nonproliferation in the Obama administration, argues that the United States could reinforce such statements by initiating a diplomatic dialogue with North Korea, if for no other reason than to clarify what specific North Korean actions—any use of nuclear weapons, for example, or any transfer of nuclear weapons to other states or terrorist groups—will invite U.S. retaliation. Maintaining these lines of communication would also help the parties avoid miscalculation in the event that North Korea takes belligerent actions that don’t clearly cross U.S. red lines. The United States engaged in similar dialogues with the Soviet Union during the Cold War.

Efforts to deter North Korea are newly urgent, but they’re not new. The North—with its bristling stockpiles of chemical weapons, biological weapons, ballistic missiles, and artillery—has not invaded the South and attempted to realize its long-stated goal of reunifying the Korean peninsula; American deterrence, starting with the troops the U.S. stationed in South Korea following the Korean War, is part of the reason why. Nor has North Korea, in the face of U.S. and allied deterrence, used nuclear weapons against South Korea and Japan since its first nuclear test in 2006.

“I categorically reject the idea that because the North Korean regime is brutal, they cannot be deterred,” said Rapp-Hooper. “When we ask whether or not a regime is deterrable, the way to answer that question is not, Do they do crazy things that we don’t like? … The core to answering that question is, Are they rational? … Can they couple means with ends? Do they look at their political objectives and select political tools and strategies that match those objectives?”

Kim Jong Un’s top objective—even above reunifying the Korean peninsula—appears to be the survival of his government, which he would clearly jeopardize by conducting a nuclear attack. “But if he’s irrational, then we worry he may do provocative things that may actually undermine the survival of the regime,” Rapp-Hooper told me. “I have not seen, nor have I heard any other North Korea or nuclear-strategy expert articulate, a case for Kim Jong Un or his grandfather or father before him [being] unable to make ends-means calculations—that is, definitionally irrational.”

Nevertheless, Rapp-Hooper added, the success of deterrence is very hard to measure “because if deterrence is working, you won’t see anything happen. But you also might not see anything happen because the adversary doesn’t feel like attacking you right now. So it’s impossible to know whether [America’s] level of current deterrence [against North Korea] is perfectly calibrated to the situation.”

The Limits of Deterring North Korea

Nine countries have or are believed to have nuclear weapons. But if North Korea becomes capable of placing a nuclear warhead on an intercontinental ballistic missile (ICBM) that can reach the United States, it will join a club of only two other nations: Russia and China. And North Korea is distinct from these countries in significant ways. While China’s relationship with the United States is at times adversarial, and Russia’s is largely so these days, North Korea is a sworn enemy of the United States. North Korea is also internationally isolated, which increases the chances of war starting by accident.

In addition, the North Korean government has a well-worn strategy of being unusually “threatening and provocative” to compensate for its military weakness relative to the U.S. and South Korean militaries. (Deterrence works both ways. There’s a reason the United States is so reluctant to go to war against a regime that, according to one retired general on Fox News at least, could be wiped out in 15 minutes.) North Korea is therefore likely to wring as much political value as possible from its nuclear weapons. It’s liable to “hold the U.S. homeland at risk so that we are terrified of doing anything that would destabilize the [Kim] regime,” Rapp-Hooper said. (The Trump administration’s challenge here is also political in nature. The vast majority of Americans view North Korea’s nuclear arsenal as a top threat to the United States. And while most Americans oppose the use of U.S. military force to take out the North’s nuclear program, preferring to impose more sanctions, there’s even greater opposition to any diplomatic agreement that accepts as fact North Korea’s possession of nuclear weapons.)

McMaster recently voiced this concern in an interview with The New Yorker, in which he once again argued that dealing with the Kim regime is different than dealing with the Soviets. “The North Koreans have shown, through their words and actions, their intention to blackmail the United States into abandoning our South Korean ally, potentially clearing the path for a second Korean War,” he warned.

This fear is well-founded, according to Rapp-Hooper. One of the most important consequences of North Korea developing a nuclear-ready ICBM is that it undermines “extended deterrence,” or the U.S. commitment to protect its faraway allies Japan and South Korea. If North Korea were to attack the South, would the United States really rush to Seoul’s defense if that meant exposing Seattle to North Korean nukes?

In this new environment, the United States will have to regularly reassure its partners in the region, and convince North Korea, that it will do what logic suggests it might not. The task is made all the more difficult by the fact that Trump has openly questioned the value of America’s alliances with Japan and South Korea, most recently accusing South Korea of “appeasement” toward the North.

The United States, however, has avoided the “decoupling” of its alliances before; in the 1960s and ’70s, it found creative ways to ease the anxiety of its European allies following the Soviet Union’s acquisition of nuclear weapons that could reach the American mainland. Back then, people wondered whether the U.S. would endanger Chicago to save Berlin.

“So, actually, what McMaster is describing ... undercuts his first comments to ABC, because what he’s suggesting is that the North Koreans are trying to use nuclear deterrence for the same purposes that we have seen other nuclear powers use their deterrents in the past—that is, to coerce for the purposes of achieving their own political ends,” said Rapp-Hooper. “That doesn’t mean we like those political ends,” but it does mean that a nuclear-armed North Korea might be more similar to other nuclear-weapons states than McMaster lets on.

Still, even if North Korea’s leaders can be deterred from using their nuclear weapons, they might conclude that those weapons give them license to engage in lower-level forms of aggression against the United States or its allies—attacking South Korean forces at sea or along the demilitarized zone between the two countries, for instance—in order to intimidate the South and sow divisions between Seoul and Washington over how to retaliate. Deterrence will also require the U.S. to build up its military presence in North Korea’s neighborhood and be on high alert for any sign, however faint, of an impending North Korean nuclear attack.

The world could thus become a more dangerous place, even if deterrence carries fewer risks than going to war with North Korea over its nuclear weapons. And chief among the dangers is miscalculation. Kim Jong Un may be generally rational, but that doesn’t mean he will always act rationally. Humans are human. As a Trump administration official recently told The New Yorker, “Saddam Hussein was not suicidal, but he committed suicide” in the lead-up to the Iraq War by underestimating the likelihood that the Bush administration would invade his country.

Miscalculation “in no way requires irrationality,” Rapp-Hooper told me. And that’s particularly true with the United States and North Korea, which for the most part don’t communicate with each other. If the United States, “in an effort to deter, or push back against North Korea’s coercion, either purposefully or inadvertently sends signals that make the [Kim] regime feel as though its future is being threatened, that is when miscalculation comes into play,” she said. In such a situation, Kim Jong Un might be incentivized to strike his adversaries first—with nuclear weapons or his other formidable military capabilities—before those stronger adversaries crush North Korea.

Nuclear deterrence has an impressive track record, but we should be cautious about how much comfort we take from past performance. “Yes, since [America’s] use of nuclear weapons against Japan, we have not had a nuclear war. We’ve had several near misses,” Jim Walsh, a nuclear-security scholar at MIT, recently observed on the Global Dispatches podcast. “Frankly, I know of no human construction, psychological or technological, that is perfect … regardless of the frailties of individual leaders, regardless of the various conditions. You’re entering the world of the religious if you believe that deterrence will work forever across all circumstances.”

“I think the North Koreans are deterrable. I think they’re containable,” Walsh argued. And yet Donald Trump and Kim Jong Un could both be described as “impulsive, thin-skinned, believing themselves to hold absolute power. I don’t know if that’s a good combination.”

“The question,” Walsh asked, “is how long can you live in perfection before someone makes a mistake?”