South Korea has long relied on the United States to keep the North Korean nuclear threat at bay. Pyongyang began taking fitful steps toward a nuclear weapon during the Cold War, tested its first bomb in 2006, and today regularly issues nuclear threats against its southern neighbor. Seoul, meanwhile, shelters under the American nuclear umbrella that came with the defense alliance it signed with Washington in 1953, just after an armistice effectively ended the Korean War. For decades, this arrangement provided South Korea sufficient security assurance. But today, that assurance appears increasingly fragile.
South Korea’s problem is twofold. First, North Korea’s capabilities are growing. Pyongyang has developed an intercontinental ballistic missile, which raises doubts about whether the United States would honor its alliance commitment and fight for South Korea, because North Korea can now strike American cities with a nuclear weapon. Second, Donald Trump, who has harshly criticized the U.S.–South Korean alliance in the past, is set to begin his second term as U.S. president. Under Trump, the likelihood that Washington would intervene in a conflict on the Korean Peninsula will drop further still.
In such a conflict, Pyongyang would almost certainly threaten nuclear attacks on American targets to deter U.S. participation. U.S. bases in the Asia-Pacific, Guam, or Hawaii would be threatened first, and then the U.S. mainland. This raises the potential cost of American assistance to South Korea far higher than it has ever been. And it is likely enough to make the United States hesitate before getting involved. Consider the war in Ukraine, where Russian nuclear threats have successfully limited U.S. support for Kyiv. If Moscow’s threats worked against the alliance-friendly President Joe Biden, then Pyongyang’s will very likely restrain the nationalist, transactional Trump. South Korea would then be left to fend for itself. To close this glaring gap in its security, Seoul is now considering a step that, until recently, was discussed only on the country’s political fringe: building its own nuclear weapons.
In South Korea, this proposal has gone mainstream. According to a Chicago Council on Global Affairs poll conducted in 2021, 71 percent of South Koreans support nuclearization, an increase from the 56 percent support the Seoul-based Asan Institute for Policy Studies found in a survey in 2010. Other polls by South Korean think tanks have found similarly decisive levels of public support. Political elites remain divided but are more sympathetic to the idea now than at any point in South Korean history.
Today, the biggest obstacle to South Korean nuclearization is not a domestic constituency but a foreign one: the United States. There is a deep, decades-old bipartisan opposition in Washington to nuclear proliferation, even among U.S. allies. In recent years, the Biden administration has tried to keep Seoul satisfied with statements reaffirming U.S. security commitments. American pressure is likely the primary reason South Korea still participates in the international Nuclear Nonproliferation Treaty (NPT), which forbids its nuclearization.
The United States has learned to live with nuclear partners before, however. The United Kingdom and France were both U.S. allies when they conducted their first nuclear tests, in 1952 and 1960, respectively, and Washington retained close ties with Israel after it developed a nuclear program in the 1960s, despite U.S. entreaties. South Korea’s anxiety over the dependability of the U.S. nuclear umbrella is also nothing new; U.S. allies had similar worries during the Cold War, when the Soviet Union threatened nuclear strikes against the U.S. mainland. But Washington’s refusal to let Seoul act on its concerns now sets the allies up for an unnecessary confrontation.
American opponents of South Korean nuclearization exaggerate the policy’s downsides, underappreciate its benefits, and ignore the United States’ own liberal values that call for Washington to tolerate a democratic partner’s national security choices, even when it dislikes them. If Seoul took this step, it would not trigger the breakdown of the international nonproliferation regime, as critics fear. North Korea’s nuclear capabilities undermine U.S. deterrence, but a South Korean nuclear arsenal can help fill the gap. A nuclear South Korea would be more self-sufficient, reducing the potential harm if Trump draws back from U.S. alliances and calming Seoul’s obsessive anxiety about the U.S. nuclear commitment.
With South Korea better able to handle the North Korean problem on its own, the United States could devote more attention to its top priority in East Asia—competition with China. But first, Washington needs to stop getting in its ally’s way and start letting Seoul make its own decisions. A South Korean decision to nuclearize could, on balance, be good not just for South Korea but also for the United States.
SAN FRANCISCO FOR SEOUL?
North Korea’s nuclear and missile capabilities have rapidly expanded since Kim Jong Un assumed leadership, in 2011. Four of the six nuclear tests Pyongyang has conducted have taken place under his leadership. Since 2017, North Korea has test-fired multiple intercontinental ballistic missiles that can hit the U.S. mainland, as well as many short- and medium-range missiles that could blanket South Korea. Pyongyang is pursuing further advances, too. It seeks to make its missiles hypersonic and its nuclear bombs smaller, perhaps with technological assistance from Russia to accelerate its progress. To improve the survivability of its nuclear forces, Pyongyang has announced its intention to put them on submarines. And it is integrating small nuclear weapons into its army, including frontline units.
North Korean strategy reflects these capability improvements. Pyongyang now routinely, almost casually, threatens to nuke South Korea and the United States. In September 2022, it promulgated a law permitting the preemptive use of nuclear weapons in the early stages of a crisis. In a speech announcing the law, Kim stated that North Korea’s nuclear status is “irreversible” and that its nuclear weapons are not a “bargaining chip” it would trade away in negotiations.
The current disparity between the North’s and the South’s nuclear capabilities destabilizes the Korean Peninsula. It encourages North Korea to bully South Korea into making concessions when crises between the two inevitably erupt.The uncertainty it generates in Seoul as to whether Washington would come to its defense in a conflict—and, in turn, Washington’s refusal to tighten its commitment to Seoul—paralyzes the alliance and opens the door to miscalculation. Inter-Korean nuclear parity would end this dangerous impasse, as Seoul would be able to deter Pyongyang without relying on questionable American guarantees.
South Korea’s arsenal would not have to be large: North Korea may be dangerous, but it is no China or Russia in terms of military strength. Seoul likely needs no more than 100 warheads to achieve local deterrence, given North Korea’s small size and small arsenal. (By comparison, Israel is estimated to have around 90 nuclear weapons.) Even now, South Korea has fighter jets capable of delivering warheads and hardened shelters to protect them. Eventually, Seoul would place its warheads undersea to improve their survivability; it already has the necessary missiles and submarines. But South Korea’s requirements end here. It does not need the heavy bombers, long-range missiles, high-yield warheads, and huge stockpiles of great powers such as the United States or Russia.
What makes South Korea’s need for a domestic deterrent so urgent is that North Korea’s nuclear and missile buildup has elevated the classic dilemma of extended nuclear deterrence: Would the United States risk its own cities to protect foreign ones? In 1961, French President Charles de Gaulle famously asked U.S. President John F. Kennedy if he would “trade New York for Paris.” Kennedy ducked the question. Today, South Korean journalists, scholars, and think tankers, as well as several members of the ruling party, publicly ask the same thing. A U.S. president, even one willing to risk San Francisco for Seoul, would face tremendous pressure from Congress and the American public not to endanger millions of U.S. civilians to aid a distant ally. South Koreans are well aware of this. A 2024 poll conducted by the Asan Institute for Policy Studies found that only 47 percent of South Koreans believe Washington would risk nuclear strikes on the U.S. homeland on South Korea’s behalf.
North Korea is not merely theoretically capable of striking U.S. targets—it almost certainly would do so if the United States joined a war to defend South Korea. Otherwise, U.S. military involvement in a second Korean war would mean the total defeat of North Korea, the unification of the peninsula, and the annihilation of Pyongyang’s ruling elite. North Korea’s army is large but technologically obsolete. Its nuclear forces are highly vulnerable to South Korean and U.S. airpower. The country is geographically small, leaving little space to retreat after losing a conventional battle at the inter-Korean border. Its population is also small and malnourished. North Korea’s economy can hardly feed its people, much less sustain a war. And the state barely functions outside the capital. After a single major conventional defeat, the North Korean regime would likely start to unravel as allied forces advanced north.
North Korean leaders therefore have no reason to hold back if a conflict were to break out. Pyongyang would issue nuclear threats against U.S. bases in East Asia and against Guam, Hawaii, and even the U.S. mainland in a desperate attempt to keep the United States out of the war—and then, if Washington joined anyway, Pyongyang would follow through on those threats. In other words, because North Korea is badly outclassed in conventional military terms, and because any serious conflict raises existential stakes for regime elites, it is far more likely than any other nuclear weapons state to actually use its weapons. It poses a unique nuclear threat.
Washington needs to stop getting in its ally’s way.
These circumstances differentiate North Korea from the Soviet Union during the Cold War and from nuclear autocracies such as China and Russia today. Those states may also be threatening, but they are much stronger than North Korea. Defeat in Ukraine or Taiwan would likely not mean the collapse of Russia or China. Thus, Moscow and Beijing’s willingness to risk the huge uncertainties of nuclear use is much lower than Pyongyang’s, as is evident in the war in Ukraine, where, despite Russian President Vladimir Putin’s threats to use nuclear weapons, it is highly improbable that he actually would.
North Korea’s reliance on its nuclear capabilities heightens doubts in South Korea about the United States’ extended deterrence. U.S. officials know this crisis of confidence exists. The Washington Declaration, a joint statement issued in 2023, sought to alleviate South Korean concerns by establishing a U.S.–South Korean Nuclear Consultative Group to bring Seoul into U.S. nuclear planning for East Asia. The United States also agreed to rotate air and sea forces more frequently through South Korea. These steps are welcome. But because they do not address the core question of whether Washington would risk nuclear retaliation to protect its ally, they offer insufficient assurance for the South Korean public and political elites.
The coming of a second Trump presidency exacerbates South Korea’s anxiety. Trump has denigrated U.S.–South Korean relations like no American president before him. During his first term, he seemed to prefer North Korea’s dictator to South Korea’s elected leader, and according to reporting by Washington Post journalists Carol Leonnig and Philip Rucker, Trump said privately in 2021 that he would “blow up” the alliance if reelected. He frequently talks about U.S. alliances as if they were pay-for-service protection schemes. In his 2024 presidential campaign, he said he would “absolutely not” defend any European country that did not meet NATO defense spending targets if it were invaded by Russia. Given all this, it is hard to imagine that Trump would risk San Francisco for Seoul.
Hoping for a calm four years while waiting out Trump’s term is not a viable option for South Korea, either. Trump has remade the GOP such that the next leader of the party would likely share his “America first” ideology, including its rejection of binding alliance commitments. The only way South Korea can hedge against the United States’ periodic swings toward isolationism, unilateralism, and transactionalism is to acquire its own nuclear defenses, thereby reducing its inordinate dependence on the United States for its security.
FALSE ALARM
Nuclearization is hotly debated in South Korea, but the think tanks, national security experts, and major media outlets that make up the country’s foreign policy community support the idea more than at any time since it was first considered in the 1970s. Indeed, advocating an independent nuclear deterrent has entered the mainstream during the administration of President Yoon Suk-yeol. Seoul’s official position is still to rely on the U.S. nuclear umbrella for South Korea’s security. But the main reason for the lack of change in its policy is the fear of U.S. retaliation, which could involve sanctions against South Korea and a weakening of the bilateral alliance.
Nonproliferation is deeply woven into U.S. foreign policy. In the past few years, the U.S. government has attempted to persuade and, if necessary, pressure South Korea not to seek nuclear weapons. In return for the United States’ agreement to ramp up bilateral security cooperation in the 2023 Washington Declaration, Seoul reaffirmed its commitment to the NPT. Outside government, too, a network of U.S. scholars, think tank researchers, activists, and former officials that support nonproliferation have engaged in parallel Track II dialogues with South Korean elites in an attempt to dissuade them from nuclearization.
The U.S. government has long maintained that the spread of nuclear weapons should be aggressively resisted. And Seoul, understandably, is wary of provoking a major breach with Washington. If South Korea is to both make progress toward a nuclear program and avoid fracturing its relationship with the United States, Washington will need to loosen its rigid opposition to allied nuclearization. This may become easier under Trump, who showed in his first term that he is inclined to throw out the script when it comes to U.S. alliances.
Most American concerns reflect general opposition to nuclear proliferation rather than specific misgivings about South Korea’s acquisition. Nonproliferation advocates hold that nuclear weapons should not spread anywhere, and in many cases argue that all countries that possess these weapons should denuclearize. This ideal of “global zero” is admirable but probably unattainable unless nuclear weapons states act first—an unlikely prospect. It is hardly fair for them to retain their weapons while demanding that all other countries remain nonnuclear, no matter their security concerns. Critics of the NPT have long suggested that the treaty amounts to nuclear discrimination because it locks in the nuclear status of early adopters while preventing other countries from building these weapons later on.
Another common concern is that South Korean nuclearization would cause the NPT to collapse. But this is purely speculative. One country has already withdrawn from the NPT—North Korea in 2003—and the treaty did not fall apart. Another departure should not destroy it, especially when the country withdrawing is one such as South Korea, a middle-sized power that has long complied with the NPT (and refrained from any rash response to North Korea’s noncompliance) but now has an obvious, justifiable reason to seek nuclear capabilities.
Seoul’s pursuit of a nuclear program would be an in-kind response to decades of North Korean misbehavior, not a rogue sprint to build a destabilizing weapon. Since 1992, when Seoul and Pyongyang issued an inter-Korean declaration to denuclearize the peninsula, Seoul has pursued that goal in good faith. Pyongyang has not. It has been sanctioned by the UN Security Council nine times for its nuclear activities and routinely makes outlandish threats about annihilating South Korea and its allies. Any international observer should be able to understand Seoul’s reasoning for pursuing a nuclear option.
Pyongyang has no reason to hold back if a conflict were to break out.
Some observers worry that, even if South Korean nuclearization did not damage the NPT, it might induce other countries in East Asia to nuclearize. This is possible but unlikely. That only nine countries have nuclearized since 1945 is strong evidence against an uncontrollable domino effect. And in South Korea’s case, its autocratic neighbors in northeast Asia—China, North Korea, and Russia—already have nukes. The only possible nearby candidates to join a nuclear cascade are Japan and Taiwan, and there is no obvious reason why South Korea’s nuclearization would encourage these fellow democracies and U.S. partners to nuclearize in response.
Taiwan’s foreign policy is structured by its relationships with China and the United States, making it unlikely to be overly concerned about this new development in South Korea. Were China to make overt nuclear threats against Taiwan, then Taipei, too, might consider going nuclear, but China, unlike North Korea, wisely avoids such extreme language. Japanese-Korean historical tensions make Tokyo and Seoul’s relationship more fraught, but if North Korean nuclearization has not pushed Japan to nuclearize for the last 18 years, it seems improbable that South Korean nuclearization would do so today. Antinuclear sentiment has also remained very high in Japan since the United States dropped two atomic bombs on the country during World War II. Ultimately, the basic condition driving South Korea’s current interest in nuclearization does not hold in either Japan or Taiwan. The debate in Seoul is driven by an acute nuclear challenge from North Korea. Neither Tokyo nor Taipei faces a comparable nuclear threat today.
Another proliferation concern is safety. With any new nuclear weapons state, there is a risk that it might store or maintain its weapons improperly or share them with other actors, intentionally or unintentionally. These general worries are legitimate, but in the South Korean case, they are not convincing. The South Korean parliament’s unanimous rejection of the president’s surprise declaration of martial law in December, as well as the swift public backlash to the measure, showed that the country’s democratic system of checks and balances is working well. South Korea’s command and control of its nuclear arsenal would be robust, and its military is under civilian authority. The country has properly managed a civilian nuclear power industry for decades, which should quell concerns about its ability to safely handle nuclear materials.
Some South Korean progressives also contend that if South Korea went nuclear, North Korea would expand its nuclear and missile programs and any possibility of a peace deal on the Korean Peninsula would disappear. This argument may have been persuasive at one time, but no longer. North Korean nuclear decisions clearly have little to do with South Korean choices; for decades, Pyongyang brazenly exploited Seoul’s nuclear restraint to build its own weapons. Kim has made clear that North Korea will never give up its nukes. At this point, South Korean threats to nuclearize are more likely than continued South Korean restraint to prompt North Korea to negotiate.
WORTH THE RISK
South Korean nuclearization is not risk-free. If Seoul began taking steps toward a nuclear program, Pyongyang might intervene to try to prevent it. The most plausible means at its disposal is major missile strikes on South Korean nuclear facilities, which would likely provoke the very conflict that North Korea acquired nuclear weapons to avoid. South Korea would ensure that its nuclear weapons program would be well defended and dispersed across the country, so only a large surprise attack by North Korea would have any hope of success. It might even have to use small nuclear weapons, because its conventional weapons might not be capable of destroying the relevant targets.
But this scenario is highly unlikely. North Korea’s goal is to forestall a conflict it would probably lose. When it threatens nuclear use, the uncertainty it creates for South Korea and the United States deters them both and wedges the allies apart. But a preemptive strike would be different. The world would turn against North Korea immediately, and any qualms about escalation would be superseded by its offensive use of nuclear weapons. There would be no way to predict how China, Russia, or the United States would respond. North Korea does not want South Korea to nuclearize, but provoking a nuclear war to stop it would entail far more risk than Pyongyang is willing to take on.
The more credible risks for South Korea are Chinese and Russian countermeasures. But Beijing and Moscow have been bad-faith partners in Korean security for decades. Both had years to try to check North Korea’s nuclear buildup and chose not to. Worse, Russia has become closer to North Korea in the last year. Moscow could seek to slow South Korean nuclearization with cyberattacks or threats to lend even more support to North Korea. But its economic leverage over South Korea is low, even more so since Seoul joined other democracies in sanctioning Russia after the latter’s invasion of Ukraine, and its international credibility is in tatters. Indeed, if Russia is assisting North Korea’s missile program, then it is contributing to the very problem driving South Korea toward nuclearization—undermining any diplomatic case Moscow may make against it.
China is less blatantly belligerent toward South Korea. But as the country with the most leverage over North Korea, its refusal to seriously punish Pyongyang for its nuclear buildup is also part of the problem that brought Seoul to this point. If Beijing were to impose sanctions on Seoul in response to nuclearization, it could inflict real pain—almost 20 percent of South Korea’s exports in 2023 were to China. South Korea’s steps to distance itself from the Chinese economy could soften the blow, however. In the first quarter of 2024, the United States narrowly overtook China as South Korea’s largest export market in 2024, in part a result of the Yoon administration’s encouragement of South Korean firms to move their operations out of China. South Korean investment in China has also dropped substantially in recent years. In 2023, China fell out of South Korea’s top five destinations for outbound investment for the first time since 1992. In short, both China and Russia are losing whatever influence they might have had to bully South Korea out of nuclearization. If they really want to prevent that outcome, they would be better off using their leverage over North Korea to reduce the threats pushing South Korea to acquire nuclear weapons.
MATURE RELATIONSHIPS
South Korean nuclearization is not only less dangerous than the United States fears but also offers strategic benefits for Washington and a salve to a strained alliance. Most obviously, a local South Korean deterrent gets the United States off the hook for direct, immediate involvement in a conflict with North Korea that could go nuclear and could draw in China. If South Korea cannot have its own nuclear weapons, then it has no option but to look to the United States for coverage. Washington’s alliance commitment thus exposes the U.S. homeland to nuclear retaliation. It is in the United States’ interest, of course, to reduce that risk.
This does not mean that the United States should abandon South Korea if it nuclearizes. The alliance between Washington and Seoul serves as a linchpin of peace and stability in the region and more broadly contributes to upholding the rules-based international order. Nuclearization is no reason to throw it away. A nuclear South Korea could play a role akin to that of France or the United Kingdom—both of which possess nuclear weapons and provide supplemental, regional deterrence within the U.S. alliance network. Paris and London can act more independently and carry more of their own risk than Washington’s nonnuclear allies. They could, for example, form the core of an independent nuclear European deterrent and help lead a European response to Russian aggression in Ukraine should Trump pull back from NATO in his second term. For now, South Korea, which has no security backstop without the United States, lacks the equivalent capacity to deal with East Asia’s nuclear powers as a peer.
U.S. leaders have long demanded that the country’s allies do more for their own defense and stop free-riding on American security guarantees—Trump most emphatically. By building its own nuclear weapons and lessening its dependence on U.S. nuclear protection, South Korea would be doing precisely that. Yet the United States has so far blocked this path to strategic maturity and responsibility.
Therein lies the core problem of Washington’s insistence that its allies adhere to nonproliferation. If U.S. partners are not allowed to make strategic choices without U.S. permission, then they will likely free-ride. It is unreasonable to expect U.S. allies to have large defense budgets and capable militaries but deny them independent strategic thinking. Strategically infantilized allies, such as Germany, are also likely to have militaries with poor capability. Berlin could afford a vastly more capable military, but it has not prioritized such spending, as was evident in its slow military response to the war in Ukraine; it has little incentive to do so, having consented to U.S. domination of NATO. Conversely, capable partners that can project power independently, such as France or India, will likely develop their own strategies, too. The United States wants the impossible: capable, big-spending allies that will do Washington’s bidding.
Allowing allies to develop and implement their own strategies is in the United States’ interest, as Washington could thus reduce its involvement in its partners’ conflicts and security problems. This leeway also reflects American values. If it wants to maintain credibility as a liberal hegemon, the United States cannot use its dominance to bully its weaker partners, as the Soviet Union did during the Cold War and China tries to do today. Washington must instead accept limits on its behavior and give its partners the freedom to make their own decisions, particularly when those partners are liberal democratic allies.
South Korea falls into that category. Public and elite support for nuclear armament will only grow as North Korea’s arsenal expands and the United States becomes an unreliable backer under Trump. If Seoul persists in seeking nuclear weapons despite U.S. efforts to dissuade it, then Washington should accept its choice.
The alternative to accommodation is for the United States to coerce South Korea into giving up on nuclearization by threatening economic sanctions and exclusion from the market for nuclear materials. Washington has run this play before with nuclear-curious allies, most notably when it headed off West Germany’s Cold War effort to build a bomb. But American threats, including suggestions that it could abandon Europe altogether, generated deep resentment in Bonn and violated the liberal principle that democracies do not coerce each other. To use the threat of sanctions to strong-arm South Korea today would similarly undermine the values that Washington’s claims distinguish democracy from autocracy—giving China more ammunition to attack the United States for hypocrisy.
PENINSULAR PARITY
An independent South Korean nuclear program is the best way to deter North Korea, but several intermediate options are on the table, too. For example, the United States might station its own tactical nuclear weapons in South Korea. This step could signal an intensified U.S. commitment to South Korean security, and it might cool public interest in full nuclearization. But the problems of U.S. extended deterrence and the fear of U.S. abandonment would remain, as the United States would retain command over these weapons, could decline to use them in a conflict, and could remove them at any time. The 2021 Chicago Council on Global Affairs survey showed only nine percent of South Korean respondents—perhaps recognizing the insufficiency of this step—supported a U.S. deployment of nuclear weapons. (Of the remaining respondents, 67 percent favored a domestic nuclear program, and 24 percent did not want nuclear weapons in South Korea at all.)
Another option is a “nuclear sharing” arrangement, which would allow the South Korean military to access U.S. warheads positioned on South Korean territory under clearly defined wartime circumstances. The idea would be to give South Korea a deterrent but limit the United States’ exposure in a conflict. North Korea and China might not accept that fine distinction, however; they might consider South Korean use of American nuclear weapons to be the same as American nuclear use. And they would likely argue as much in an effort to derail this option. Ultimately, nuclear sharing is only slightly better than redeploying U.S. tactical nukes to South Korea and keeping them under U.S. control.
The next step up the ladder is “nuclear latency,” a compromise position that is growing in popularity among pronuclear South Korean politicians such as Han Dong-hoon and Yoo Yong-won of South Korea’s ruling People Power Party. In this scenario, South Korea would develop the capability to quickly build nuclear weapons but would not actually do so. Reducing Seoul’s “breakout time” would not violate the NPT. But this solution has its own difficulties. If South Korea’s breakout time is too long, then its latent nuclear capabilities cannot provide the desired deterrent effect. But if its breakout time is sufficiently short, then latency is nuclearization in all but name, and South Korea would face the international backlash without capturing the full security benefits.
South Korean nuclearization need not cause a rupture with the United States.
The best option is still for South Korea to build enough survivable nuclear weapons to achieve local deterrence and restore inter-Korean nuclear parity. Assembling even a limited arsenal would give South Korea greater strategic independence and reduce its constant anxiety over the shifts in U.S. foreign policy. It would relieve the United States from its commitment to immediately join a conflict when its very participation would worsen nuclear escalation pressures. And it would block North Korea from trying to use its nuclear advantage to score gains from South Korea during crises. Washington and Seoul’s relationship would be more balanced and mature. The United States, which worries about free-riding allies and overextending itself, could reduce its responsibility for South Korean security.
The very outcome that ought to benefit Washington may also be what it fears most. It is possible that an unwillingness to cede paramount authority in South Korea is driving U.S. opposition to Seoul’s nuclearization even more than are dubious concerns about proliferation. Nuclearized partners, such as France, India, and Israel, are more difficult for the United States to dominate. Yet in the case of South Korea, the strategic benefits to Washington should outweigh its fear of losing control.
South Korean nuclearization need not cause a rupture with the United States unless Washington chooses to create one. As South Korea’s primary security partner and longtime political patron—and running neck and neck with China to be South Korea’s biggest export market—the United States wields an informal veto. It has already tried to dissuade Seoul, reassure it, and vaguely threaten it. None of this has worked. Trump’s return will only deepen Seoul’s nuclear interest; just two days after his reelection, South Korea’s largest daily newspaper ran an editorial suggesting that the country might need its own nuclear weapons.
Washington’s moves have failed to resolve the core security problems that a South Korean program can redress: North Korea’s relentless march toward ever more powerful weapons of mass destruction and the United States’ unreliability in (and likely after) the Trump era. The United States itself would never tolerate the nuclear vulnerability South Korea now experiences. Rather than insisting that its ally remain imperiled, Washington should drop its barriers to Seoul’s finding its own way to security.