The Importance of Sustaining Peace on the Korean Peninsula and Strengthening the ROK–U.S. Alliance Amid Recent Developments in the Middle East

Kim TaeJoon

Director, Institute for Korean Peninsula Security Studies

Professor Emeritus, Korea National Defense University

Prologue: From the Strait of Hormuz to the Korean Peninsula—A Connected Front Line

March 2026: The flames of conflict are intensifying in the Persian Gulf. Large-scale airstrikes conducted by the United States and Israel against Iran have inflicted significant damage on its nuclear facilities and military infrastructure. Nevertheless, the Iranian regime remains intact, and the conflict appears to be extending beyond initial expectations. Many in South Korea may perceive this as a regional conflict confined to the Middle East; however, this perception is misguided.

What is unfolding in the Strait of Hormuz is directly linked to the security of the Korean Peninsula. More than 70% of South Korea’s energy imports transit this maritime chokepoint. The cautious posture adopted by major states—despite U.S. requests for allied contributions to maritime escort and mine-clearing operations—underscores that trust within alliances cannot be taken for granted. Such fissures in trust bear directly on the credibility of extended deterrence on the Korean Peninsula. The front lines are interconnected.

Part 1. The Flames of the Middle East—The Current Phase of the Iran War and the Silence of Allies

The U.S. military has conducted precision strikes against dozens of key targets, including military infrastructure such as the airport and runway on Kharg Island, integrated air defense systems, the Jassan naval base, and missile and mine storage facilities.

The amphibious assault ship USS Tripoli (LHA-7), carrying approximately 2,500 Marines from the 31st Marine Expeditionary Unit, is also en route to the Middle East and is expected to be deployed to waters near the Strait of Hormuz in the near term. A classic strategy of “coercive diplomacy” is evident, leveraging Kharg Island—through which the majority of Iran’s oil exports pass—as a point of pressure to compel Iran to negotiate.

However, despite this overwhelming military advantage, the United States appears to be experiencing a degree of political isolation. On March 17, 2026, President Trump publicly criticized the limited response from allies in statements issued by the White House and on his social media platforms, expressing dissatisfaction that even modest naval contributions for maritime escort and mine-clearing operations had not materialized. This should be understood not merely as rhetorical frustration, but as an indicator that the U.S.-led multinational maritime security framework is not functioning as intended.

In practice, although the United States has explicitly called upon major powers—including South Korea, Japan, China, the United Kingdom, and France—to participate, each has maintained a cautious stance, citing its own strategic considerations. European actors, in particular, tend to frame the situation as a localized conflict, with some explicitly ruling out military involvement.

As a result, participation has remained limited. That the world’s preeminent military power has been unable to secure even modest allied contributions—on the order of “a few minesweepers”—underscores emerging strains within the contemporary alliance system and highlights the evolving realities of burden-sharing.

Part 2. A Shaky Alliance—Trump’s Credibility Crisis and the Dilemma of Extended Deterrence

Allies’ reluctance to become involved reflects more than simple risk aversion. A more fundamental factor is the erosion of confidence in President Trump’s statements and policy direction. He has conveyed inconsistent signals—at times suggesting an early termination of the conflict, while at others indicating preparations for a protracted engagement—and has alternated between raising the prospect of negotiations and rejecting them on the grounds that requisite conditions have not been met.

As instances of post-agreement policy reversals have accumulated in prior diplomatic engagements, concerns regarding the predictability of U.S. policy have intensified among allied governments. His repeated sharp criticisms of NATO and other key allies have further reinforced these perceptions.

Under such circumstances, if a country were to participate in deployments only to face a sudden U.S. declaration of mission termination and force withdrawal, it could be left to bear the operational and strategic burden vis-à-vis Iran on its own. This extends beyond conventional military risk; it suggests that participation in joint operations with a partner whose reliability is in question may itself constitute a strategic liability. This concern lies at the core of allied hesitation.

South Korea is thus confronted with a more consequential question: if the Trump administration continues to signal diminished reliability to its allies, what are the implications for security on the Korean Peninsula? To what extent can extended deterrence—the commitment that the United States will respond alongside South Korea in the event of a North Korean nuclear or missile provocation—be regarded as credible? Alliance credibility is not established through declaratory policy alone, but through the consistent accumulation of actions. It is therefore difficult to dismiss the possibility that patterns of policy execution observed in the Strait of Hormuz could manifest in a similar manner in future contingencies on the Korean Peninsula.

Part 3. North Korea’s Multifaceted Military Advancements and the Security Vacuum on the Korean Peninsula—Expanding Threats and Diminishing Deterrence

3-1. The Advancement in North Korea’s Nuclear and Missile Capabilities

On March 18, 2026, Director of National Intelligence Tulsi Gabbard issued a clear warning during testimony before the Senate Intelligence Committee: “North Korea’s ICBMs can already reach the U.S. mainland, and it remains committed to expanding its nuclear arsenal.”

In 2025 alone, North Korea reportedly generated approximately $2 billion (roughly 3 trillion won) through illicit cryptocurrency activities and redirected these resources into its strategic weapons programs. It is also pursuing the development of hypersonic glide vehicles (HGVs) and multiple independently targetable reentry vehicles (MIRVs), designed to penetrate U.S. and regional missile defense systems.

3-2. Naval Power Enhancement—The Introduction of the Choe Hyun and Nuclear Submarines

The threat posed by North Korea is no longer confined to nuclear weapons and ballistic missiles. In 2025, Pyongyang undertook a broad military modernization effort, marked by a particularly notable qualitative shift in its naval capabilities.

On April 25, 2025, North Korea launched the Choe Hyun, a new 5,000-ton-class destroyer. As the first platform in the Korean People’s Navy reportedly equipped with phased-array radar and vertical launch systems, the vessel demonstrated an unusually rapid operational tempo, conducting live-fire testing within five days of its launch.

The Choe Hyun is assessed to be equipped with supersonic cruise missiles, an integrated ship-based air defense system, and a 127mm automatic deck gun. The configuration of its radar and air defense systems bears similarities to Russian naval platforms, raising the possibility of external technical assistance. Kim Jong-un personally observed the test and directed that efforts to “accelerate the nuclear armament of the Navy” be intensified.

In March 2026, Kim Jong-un again observed a test launch of a strategic cruise missile from the Choe Hyun. The missile reportedly struck a target in the West Sea after a flight lasting approximately 2 hours and 48 minutes. Analysts assess the system to be the Hwasal-3, with an estimated range of 2,000–2,500 kilometers. This capability extends beyond the Korean Peninsula, conveying a broader strategic signal aimed at U.S. military installations in the region—including Guam—and potentially beyond.

North Korea’s nuclear-powered submarine capabilities are also advancing rapidly. On December 25, 2025, Pyongyang unveiled, for the first time, the full hull of an 8,700-ton-class strategic nuclear submarine. The sail is assessed to accommodate up to ten submarine-launched ballistic missile (SLBM) tubes.

Once operational, such a platform would provide North Korea with a credible second-strike capability. Some analysts have suggested that the small modular reactor technology required for such systems may have been acquired with external assistance, potentially from Russia.

3-3. Constitutionalizing Hostility—The “Two Hostile States” Doctrine

North Korea’s military advancement is not the product of episodic or accidental provocation, but rather an expression of systemic intent. Through its 2023 constitutional amendment, North Korea formally codified its status as a nuclear-armed state and inserted a provision into Article 58 defining the Republic of Korea as a “hostile state.”

In doing so, it has effectively foreclosed space for dialogue and negotiation, while institutionalizing the legitimacy of its military buildup. This constitutes not a tactical adjustment but a strategic declaration, and the underlying structure of the threat is unlikely to change in the near term.

3-4. The Security Vacuum on the Korean Peninsula Created by the War in the Middle East

What warrants closer scrutiny is the evolving strategic environment. The United States is currently concentrating a significant portion of its strategic assets on the conflict in the Middle East. The aircraft carrier USS Gerald R. Ford has withdrawn from the operational theater due to a fire, while ammunition constraints and cumulative fatigue from sustained operations are becoming increasingly evident.

Since the onset of the Iran conflict, the redeployment of U.S. Forces Korea air defense assets to the Middle East has begun, and reports indicate that, following Patriot systems, elements of the THAAD system have also been repositioned. The longer the conflict persists, the more U.S. strategic attention and resources are likely to remain committed to the Middle East.

Director Gabbard assessed that “support from Russia, China, and North Korea during the Iran conflict has been far more limited than anticipated,” but this does not suggest any diminution in North Korea’s propensity for provocation. On the contrary, Pyongyang may interpret the current environment—characterized by a diversion of U.S. strategic focus—as an opportunity. Security on the Korean Peninsula does not exist in isolation. As the conflict in the Middle East endures, the relative level of deterrence applied to the Korean Peninsula is correspondingly reduced.

3-5. South Korea’s Security at a Crossroads—Expanding Threats, Shrinking Defenses

While North Korea is advancing its military capabilities across multiple domains, the internal realities of the South Korean military reveal a growing structural imbalance. The most fundamental issue is the sharp decline in personnel strength. According to data from the Ministry of National Defense, South Korea’s active-duty force has decreased by approximately 110,000 over a six-year period, from 560,000 in 2019 to 450,000 as of 2025.

During this period, 17 division-level or higher units have been disbanded or consolidated, and the officer accession rate, which stood at approximately 90% in 2019, declined to around 50% by 2024. Demographic decline is thus directly eroding national defense capacity.

This challenge is compounded by issues of morale within the force. Reports from the field increasingly indicate the emergence of a structural condition in which the sense of duty and pride in national defense is insufficient to offset perceived deprivation.

At the same time, the U.S. 2026 National Defense Strategy (NDS) outlines a framework in which primary responsibility for deterring North Korea shifts increasingly to South Korea, with the expectation that South Korean forces will be capable of independently sustaining defense operations for at least 30 days prior to the arrival of U.S. reinforcements. However, given the concurrent realities of force reductions, difficulties in officer recruitment, and emerging gaps in air and missile defense, this expectation risks remaining aspirational rather than operationally feasible.

Threats are expanding, while the forces tasked with deterrence are contracting, and the morale underpinning those forces is under strain. This is the reality of security on the Korean Peninsula in 2026. The unveiling of North Korea’s nuclear-powered submarine, the strategic cruise missile launches from the Choe Hyun, and the redeployment of U.S. Forces Korea air defense assets to the Middle East—taken together—render public concern in South Korea both understandable and grounded in reality.

Part 4. The ROK-U.S. Alliance: What Must Be Done Now?

4-1. The Dilemma of Troop Deployment and the Cost of Inaction

South Korea’s dilemma is both concrete and immediate. All 12 of its naval minesweepers are small vessels of 700 tons or less, limiting their capacity for sustained independent operations. Deploying a task group of at least three vessels, including an Aegis destroyer, would require approximately 600 to 900 personnel and would necessarily create a corresponding capability gap vis-à-vis North Korea. While the military costs of deployment are significant, the diplomatic costs associated with inaction may be even greater.

It is accurate to note that President Trump’s actions have, at times, undermined perceptions of U.S. credibility. However, this does not provide a sufficient basis for South Korean inaction. Alliances are inherently reciprocal. Should South Korea respond to U.S. requests with sustained reluctance or passivity, its moral and diplomatic standing to invoke U.S. extended deterrence in the face of North Korea’s nuclear threat would be correspondingly weakened. Alliance credibility is tested—and ultimately demonstrated—during periods of crisis. The present moment is such a test.

4-2. A Strategy of Conditional Participation—Designing Leverage

The appropriate course lies neither in unconditional participation nor in outright refusal. A prudent approach is to leverage the 17-year record of the Cheonghae Unit as a diplomatic asset, employing conditional participation in mine-clearing operations as a source of bargaining leverage. The critical issue is one of sequencing and form. Committing to participation in advance and seeking conditions thereafter effectively relinquishes leverage; it is therefore essential to secure clearly documented commitments ex ante.

For example, conditions such as the institutionalization of the ROK-U.S. Extended Deterrence Strategy Consultative Group (EDSCG), an increased frequency of rotational deployments of strategic assets—including strategic bombers and SSBNs—to the Korean Peninsula, and the strengthening of the operational substance of the Nuclear Consultative Group (NCG) should be explicitly codified. In addition, efforts to secure a more favorable position in defense cost-sharing negotiations should be integrated into this framework.

4-3. Restoring Confidence in Extended Deterrence—Pathways to Alleviating Public Anxiety

Confidence in extended deterrence rests on three pillars: capability, will, and communication. The United States’ nuclear capability remains overwhelming; the principal concerns lie with will and communication. President Trump’s unpredictable pattern of public statements has contributed to doubts regarding U.S. resolve, while the redeployment of air defense assets has created a perception of a communication gap. Restoring these two elements constitutes a central task for South Korea’s foreign and security policy.

Through the regularized operation of the Nuclear Consultative Group (NCG), a framework should be established that enables South Korea to participate more substantively in U.S. nuclear decision-making processes during crisis contingencies.

4-4. Securing Strategic Autonomy Between the United States and China

South Korea must carefully secure strategic autonomy within the broader context of U.S.–China strategic competition. It is necessary to assess with precision the potential ramifications that participation in operations related to Iran may have for China.

Beijing could interpret South Korea’s deployment to the Strait of Hormuz as a signal of full alignment with the United States, potentially generating diplomatic and economic frictions comparable to those experienced during the THAAD dispute. Accordingly, a calibrated approach is required—one that clearly defines the nature of such deployment as a “contribution to humanitarian maritime security” and communicates this position in advance through diplomatic channels to minimize misperceptions.

4-5. Securing Domestic Political Consensus and the Role of the National Assembly

The decision to deploy forces extends beyond an executive policy determination; it is a matter that requires national consensus. A deployment undertaken in the absence of domestic political support is unlikely to be sustainable. As demonstrated by the cases of the Iraq (2003) and the Afghanistan (2001) deployments, the diplomatic impact of alliance contributions is maximized when supported by public consensus and legislative approval.

The government must therefore present, in a transparent manner, the basis for its strategic assessment through close consultation with the National Assembly’s Foreign Affairs and Security Committee and the National Defense Committee, thereby ensuring the legitimacy and durability of the policy.

This approach—simultaneously accounting for post-conflict relations with Iran, the potential security vacuum vis-à-vis North Korea, and the need to preserve strategic autonomy between the United States and China—represents the most realistic and balanced course of action available to South Korea. A crisis presents both risks and opportunities; if managed proactively, it can reinforce the ROK–U.S. alliance and substantively strengthen deterrence on the Korean Peninsula.

Epilogue: Peace on the Korean Peninsula Cannot Be Maintained on Its Own

“Advance without seeking glory; retreat without evading responsibility; protect the people and serve the interests of the state—this is the treasure of a nation.” — The Art of War

Peace on the Korean Peninsula has been sustained for more than seven decades on the foundation of the ROK-U.S. alliance; yet that foundation is not immutable. President Trump’s unpredictability, the protracted conflict in the Middle East, North Korea’s advancing nuclear and naval capabilities and the constitutional codification of hostility, and the intensifying dynamics of U.S.-China strategic competition are all unfolding simultaneously. Under these conditions, the need for proactive alliance management has become more acute than at any point in recent memory.

As North Korean nuclear-powered submarines operate below the surface, as its 5,000-ton-class destroyer, the Choe Hyun, conducts strategic missile launches in the Yellow Sea, and as U.S. air defense assets stationed in South Korea are redeployed to the Middle East, both the morale and operational capacity of the South Korean military are coming under mounting pressure. Public concern is therefore well-founded. Addressing this concern requires more than rhetorical reassurance; it demands the restoration of credible, tangible deterrence—and the starting point for such restoration lies in strengthening and actively managing the ROK–U.S. alliance.

Passivity is not a viable option. Alliances that are not actively managed risk gradual erosion. Before the reverberations from the Strait of Hormuz reach the Korean Peninsula, South Korea must undertake a clear-eyed assessment of its strategic choices and act decisively. History records those nations that act with resolve—and imposes costs on those that fail.