By Ephraim Agbo
For more than seven decades, the Korean Peninsula has existed in an uneasy state of suspended conflict. The Korean War ended with an armistice in 1953, but no formal peace treaty was ever signed, leaving the two Koreas technically divided by a conflict that has never been fully resolved. At the centre of this fragile arrangement has been the United States, whose military presence in South Korea has provided both a physical shield against North Korea and a political guarantee that any major attack on the South would almost certainly trigger an American response. Over the decades, successive Republican and Democratic administrations have maintained that commitment. Donald Trump's decision to substantially reduce joint military exercises with South Korea, however, is forcing a new examination of what that commitment actually means and whether the security architecture built after the Korean War is beginning to change.
The immediate controversy surrounds Ulchi Freedom Shield, the annual military exercise conducted by the United States and South Korea. Although such exercises are often presented as demonstrations of military strength, much of the training is based on computer simulations, command-post exercises and operational planning. The purpose is to determine whether American and South Korean forces could function effectively together in the event of a major crisis. Communications systems are tested, intelligence is shared, command structures are evaluated, logistics are examined and military units practise responding to simulated attacks. The value of the exercise, therefore, lies less in the spectacle of troops and weapons and more in the readiness it creates for a situation in which decisions may have to be made within minutes.
That is why a reduction in the exercises is strategically significant. It could lower tensions with North Korea and create space for diplomacy, particularly because Pyongyang has consistently condemned American-South Korean military drills as rehearsals for invasion. But military exercises also provide an opportunity for the allies to identify weaknesses before an actual conflict exposes them. The issue is therefore not whether reducing military activity is inherently good or bad. The more important question is whether the reduction is accompanied by diplomatic progress and alternative measures that preserve deterrence. If the answer is no, Washington could find itself giving North Korea one of its longstanding demands without obtaining a corresponding concession in return.
An Alliance Built on Deterrence
The American military presence in South Korea was born from the catastrophe of the Korean War. In 1950, North Korean forces crossed into the South in an attempt to reunify the peninsula by force. The United States intervened under a United Nations command, helping prevent the collapse of South Korea and eventually pushing North Korean forces back. The conflict ended three years later with an armistice, but the absence of a peace treaty meant that the military confrontation never truly disappeared. Instead, it became institutionalised through the heavily fortified border, the presence of American troops and the permanent military cooperation between Washington and Seoul.
That arrangement has always been about more than defending South Korean territory. American forces in the country have served as a form of strategic tripwire. Their presence means that a large-scale attack on South Korea would almost certainly involve American personnel from the beginning, making it far more difficult for Washington to remain outside the conflict. The calculation is intended to discourage Pyongyang from believing that it could launch an attack while keeping the United States out of the war. In this sense, American troops are not simply a military force; they are also a political message about the consequences of aggression.
The alliance has another important component: extended nuclear deterrence. South Korea has accepted the protection of the American nuclear umbrella rather than developing its own nuclear arsenal. The arrangement has been one of the foundations of security in Northeast Asia. Washington provides the strategic deterrent, while Seoul concentrates on maintaining a formidable conventional military capability. The system has helped prevent the emergence of another nuclear-armed state in the region, despite the fact that South Korea lives next to a country that has spent decades developing nuclear weapons and long-range missiles.
The Credibility Problem
The difficulty is that deterrence depends on credibility as much as capability. It is not enough for the United States to possess nuclear weapons or maintain a powerful military. South Korea must believe that Washington would actually be prepared to use its power, and potentially accept enormous risks, if the South were attacked. That confidence is central to the alliance. Once doubts emerge about whether an American president would honour the security commitment under extreme circumstances, the calculations of both allies and adversaries begin to change.
This is why Trump's approach has generated concern beyond the immediate question of military exercises. If South Korean policymakers begin to believe that American commitments are increasingly conditional on Seoul's willingness to satisfy Washington on unrelated issues, pressure for greater strategic independence could grow. South Korea already possesses a highly advanced industrial base, sophisticated missile technology, a strong conventional military and a developed civilian nuclear sector. It does not currently possess nuclear weapons, but the debate over whether it should eventually develop them has never completely disappeared from South Korean politics and public opinion.
A serious deterioration in confidence could therefore produce consequences that Washington may not intend. If South Korea moved towards an independent nuclear deterrent, Japan would have to reassess its own security environment. China would face another nuclear-capable neighbour. North Korea would almost certainly use South Korea's nuclearisation to justify further expansion of its own arsenal. The result could be a nuclear competition across East Asia, precisely the opposite of the strategic stability the United States has spent decades trying to maintain.
Trump’s Transactional View of Alliances
The Korean dispute is also part of a much larger change in the way Trump approaches America's alliances. He has repeatedly questioned whether wealthy American partners contribute enough to their own defence and has argued that countries benefiting from U.S. protection should assume greater responsibility for maintaining their security. Under the traditional American approach, alliances have largely been presented as long-term strategic commitments built around shared interests and common threats. Trump's approach is more transactional. The question is increasingly not simply what the United States can do for an ally, but what the ally is prepared to do for the United States.
That difference has become particularly visible in Trump's criticism of South Korea over the conflict involving Iran. Washington has argued that South Korea, as a major economic and military power with significant interests in global energy routes, should be prepared to contribute more directly when American forces are engaged in a major conflict. Seoul's calculation is considerably narrower. South Korea's most immediate security threat is North Korea, not Iran, and the South Korean government has to consider whether involvement in a distant conflict could expose the country to risks that have little direct connection to its national defence.
The disagreement illustrates a fundamental problem within modern alliances: countries can share a treaty without sharing identical strategic priorities. Washington increasingly views threats involving Iran, Russia, China and North Korea as interconnected elements of a wider global competition. Seoul, however, still has to live with the reality of a nuclear-armed North Korea immediately across the Demilitarized Zone. What Washington sees as burden-sharing, Seoul may see as a diversion from its most immediate security responsibility. Neither perspective is necessarily irrational, but the difference can become dangerous if it is allowed to undermine trust.
A Message to Seoul and Pyongyang
Trump's decision can therefore be interpreted as sending two messages at the same time. To South Korea, it signals that American protection will increasingly be accompanied by expectations that Seoul should contribute more to its own defence and to broader American strategic objectives. To North Korea, it signals that Washington is willing to reconsider some of the military activities Pyongyang has long regarded as provocative if doing so can create an opening for negotiations.
If managed carefully, this could be an effective bargaining strategy. Trump could reduce some of the military pressure on North Korea while demanding meaningful concessions in return, potentially reopening the diplomatic channel that collapsed after his first-term summits with Kim Jong-un. The danger is that the two sides could interpret the same American decision in completely different ways. Pyongyang may see the reduction as evidence that its nuclear arsenal has successfully forced Washington to modify its behaviour, while Seoul may see it as evidence that the American commitment is becoming less predictable.
That kind of ambiguity can gradually weaken deterrence even without a single dramatic military incident. An adversary does not need to believe that America will never intervene. It only needs to become less certain that America will intervene decisively. Over time, that uncertainty can change military calculations, encourage risk-taking and create opportunities for misjudgement.
The Lessons of Trump’s First Dealings With Kim Jong-un
Trump's previous engagement with Kim Jong-un demonstrates both the possibilities and limitations of personal diplomacy. The Singapore summit in 2018 was unprecedented: a sitting American president met face-to-face with the leader of North Korea, something that had been considered almost impossible under previous administrations. The images from that meeting created a sense that decades of hostility could be replaced by direct dialogue. Yet the symbolism proved easier to achieve than the substance. The two governments could agree on broad principles, but they could not resolve the fundamental dispute over North Korea's nuclear arsenal and the sanctions imposed on Pyongyang.
The problem became clearer at the Hanoi summit in 2019, when the negotiations collapsed without a final agreement. North Korea wanted significant sanctions relief and other concessions, while the United States demanded much more substantial restrictions on its nuclear programme. The two positions remained too far apart. The episode demonstrated the central limitation of leader-to-leader diplomacy: presidents can create momentum, but they cannot simply erase the underlying strategic interests of the countries they represent. A personal relationship can open negotiations, but it cannot by itself resolve the question of what North Korea is prepared to surrender or what Washington is prepared to offer.
North Korea Is Not the Same Adversary
Any new attempt at diplomacy must also recognise that North Korea has changed since Trump's first presidency. Its nuclear and missile programmes have continued to develop, and its strategic relationship with Russia has deepened. North Korean involvement in Russia's war against Ukraine has also exposed its forces to modern battlefield conditions, potentially giving Pyongyang valuable experience in areas such as drone warfare, electronic warfare and battlefield intelligence.
That development matters because modern warfare has changed dramatically. Drones, cyber operations, electronic disruption, precision targeting and real-time intelligence increasingly determine battlefield outcomes. A military that learns these techniques through actual combat acquires knowledge that conventional exercises cannot completely replicate. If North Korea is gaining that experience through its relationship with Russia, the United States and South Korea have to consider not only the size of North Korea's arsenal but also the evolving sophistication of the forces that operate it.
North Korea's growing relationship with Russia also gives Kim Jong-un a potentially stronger diplomatic position. The country is not completely isolated in the way it once appeared to be. Its relationships with Russia and China provide alternative diplomatic and economic channels, while its nuclear arsenal gives it a strategic capability that cannot easily be ignored. This makes the old formula of pressure followed by demands for denuclearisation considerably more difficult to reproduce.
China Is Watching Closely
The Korean Peninsula cannot be separated from the wider competition between the United States and China. Beijing does not want another war on its doorstep, but it also does not want the United States to maintain overwhelming military dominance directly beside Chinese territory. A reduction in American-South Korean military activity could therefore serve some Chinese interests by lowering military tensions in the region.
But Beijing could also interpret a weakening American commitment to South Korea as a sign that Washington is becoming less willing to bear the costs of maintaining its alliances. That would have consequences well beyond Korea. Japan, the Philippines, Australia and other American partners would inevitably examine the situation and ask whether their own security guarantees could eventually become conditional.
This is why the credibility of the American alliance system cannot be measured only by the number of American troops stationed in one country. It is also measured by what other countries believe those troops represent. If allies begin to doubt that Washington will remain committed when the costs become high, they will begin developing alternatives, whether through greater military spending, deeper regional partnerships or, in the most extreme cases, nuclear deterrence.
The Risk of “Korea Passing”
One of South Korea's greatest concerns would be the possibility of becoming a secondary player in negotiations that directly determine its security. The fear sometimes described as “Korea passing” is that Washington and Pyongyang could reach an understanding based primarily on their own interests while Seoul is left to deal with the consequences.
That would create an extraordinarily difficult position for South Korea. Seoul wants peace and has an obvious interest in reducing tensions with Pyongyang. Another war would be catastrophic for the South Korean economy and population. But peace cannot simply mean reducing pressure on North Korea. It must also provide credible assurances that South Korea will not become more vulnerable as a result of diplomacy.
This is why South Korea's role in any future negotiations will be crucial. A sustainable agreement cannot simply be designed in Washington and Pyongyang and presented to Seoul as a finished product. South Korea is not merely the territory on which the conflict would take place. It is a sovereign military and economic power with its own interests, capabilities and strategic calculations.
The Paradox of Greater South Korean Independence
Trump's pressure on Seoul could also produce an unintended consequence: greater South Korean military independence. Encouraging South Korea to spend more on defence is one thing; convincing South Korea that it must ultimately rely less on America is another.
If Seoul concludes that American commitments have become too dependent on the political preferences of individual presidents, it could accelerate efforts to build greater strategic autonomy. That could mean stronger conventional forces, greater missile capabilities and more independent defence planning. In the long term, however, it could also intensify the domestic debate over whether South Korea should possess its own nuclear deterrent.
Such an outcome would represent a profound change in the relationship. The United States might succeed in getting South Korea to assume more responsibility for its own defence, only to discover that a more self-reliant South Korea is also more willing to pursue an independent foreign and security policy.
The Real Test of Trump’s Strategy
The success or failure of Trump's strategy will ultimately be determined by what happens after the military exercises are reduced. Does Kim Jong-un return to serious negotiations? Does North Korea offer meaningful limits on its nuclear and missile programmes? Does Washington provide incentives substantial enough to make those concessions worthwhile? Does South Korea remain fully involved in the process? And can the United States reduce military tensions without weakening the credibility of its defence commitment to Seoul?
If those elements come together, Trump's approach could prove consequential. A renewed diplomatic process could lower tensions and potentially establish a more stable relationship between Washington and Pyongyang. It might not produce complete denuclearisation, but even meaningful arms-control measures, communication channels and mechanisms for preventing accidental conflict could represent significant progress.
The opposite outcome would be much more troubling. If North Korea accepts reduced military pressure while continuing to expand its nuclear and missile capabilities, Washington would have given Pyongyang a strategic concession without obtaining an equivalent commitment. South Korea could become less confident in the alliance, Japan could reconsider its own security options and China could perceive an opportunity to expand its influence. The resulting instability would not necessarily produce an immediate war. It could be something more gradual: an erosion of the assumptions that have maintained stability for decades.
A Gamble That Extends Beyond Korea
There is therefore a legitimate argument that the Korean Peninsula needs a different diplomatic approach. More than seventy years of deterrence have prevented another full-scale war, but they have not eliminated North Korea's nuclear weapons or created a permanent peace. The traditional strategy has achieved an important objective — preventing another Korean War — but it has failed to resolve the underlying political conflict.
Trump's willingness to engage Kim Jong-un directly could create an opportunity that conventional diplomacy has struggled to produce. But diplomacy must not become a substitute for strategy. Reducing military activity without reducing the underlying threat is not necessarily peace; it may simply change the appearance of confrontation.
The challenge is to maintain enough military capability to make aggression unattractive while creating enough diplomatic space to make restraint worthwhile. That requires Washington to reassure Seoul while engaging Pyongyang. It requires South Korea to remain central to negotiations. It requires North Korea to understand that economic and diplomatic benefits must be tied to concrete actions. And it requires the United States to demonstrate that its alliances remain credible even as it demands greater contributions from its partners.
The Question That Matters Most
The Korean Peninsula has remained relatively stable for more than seven decades because the major powers involved have understood the catastrophic consequences of miscalculation. North Korea possesses nuclear weapons. The United States has an extensive military presence in South Korea. China remains a major regional power. Russia has deepened its relationship with Pyongyang. Japan remains a major economic and military power. Any serious conflict would therefore have consequences far beyond the two Koreas.
Trump is now testing whether this security architecture can be modified without destabilising it. His strategy rests on several assumptions: that personal diplomacy can succeed where conventional pressure has failed; that America's allies should assume greater responsibility for their own security; and that reducing military confrontation can create space for negotiations.
Those assumptions may prove correct. But they also carry considerable risks.
If the strategy succeeds, Trump could demonstrate that one of the world's longest-running military confrontations can be managed through a combination of diplomacy, deterrence and greater burden-sharing. If it fails, the consequences could include a more confident nuclear North Korea, a more strategically independent South Korea, a more anxious Japan and a less certain American alliance system across the Indo-Pacific.
The central question, therefore, is not simply whether reducing military exercises is the right decision. It is whether Washington can reduce the temperature of confrontation without reducing the credibility of deterrence.
That distinction could determine whether the Korean Peninsula moves towards a genuine diplomatic opening or enters a new era of strategic uncertainty.
For seventy years, the American-South Korean alliance has rested on a basic bargain: Washington provides extended security guarantees and military power, while Seoul remains a critical partner in maintaining stability on the peninsula. Trump is now testing whether that bargain can be rewritten without destroying the confidence on which it depends.
And in a region where nuclear weapons, unresolved conflict, competing superpowers and increasingly uncertain alliances already intersect, the consequences of getting that balance wrong could extend far beyond Korea.