The U.S. Request for Troop Dispatch to the Strait of Hormuz and South Korea’s Principle of Non-Intervention in War: A Risk Management Strategy for U.S. Relations

Executive Summary

Amid a prolonged military stalemate between Iran and the United States, the South Korean government is buying time by deferring a decision on troop deployment. While President Lee Jae-myung’s principle of “non-intervention in war and combat” reflects domestic anti-war sentiment, the Blue House quickly clarified that this was not a rejection of President Trump’s request for cooperation. The National Security Council (NSC) Standing Committee’s decision to remove the troop dispatch proposal from its agenda demonstrates that domestic political factors, namely declining approval ratings, are driving security and foreign policy decisions. As the Trump administration links Seoul’s non-cooperation on Iran to negotiations on defense cost-sharing and investment in the U.S., the key to maintaining leverage is to address these issues on separate tracks. Going forward, South Korea should maintain its principled non-interventionist stance while preemptively designing a contribution plan limited to non-combat and freedom of navigation support missions, carefully timing any announcement to align with the evolving stalemate.

I. Analysis of the Current Situation

The Request for Troop Dispatch to the Strait of Hormuz and South Korea’s “Non-Intervention in War” Stance

1. Background and Developments

The current crisis began with a U.S.-Israeli airstrike on Iran on February 28, 2026 [3][6], which killed Supreme Leader Khamenei [3][6]. However, the regime change sought by the United States did not materialize [3][6]. After six months of military operations failed to bring about the regime’s collapse, the U.S. shifted its strategy toward economic warfare [3][6].

On June 17, President Trump and the Tehran government signed the “Islamabad Memorandum,” which stipulated an immediate and permanent cessation of military actions on all fronts [6][9]. Immediately after signing, President Trump posted on social media, “Ships of the world, start your engines” [6]. However, the memorandum expired on August 17 [3][6]. Iran subsequently adopted a more aggressive posture, and tensions in the Strait of Hormuz escalated again [3][6].

The South Korean government’s involvement dates back to April, when it joined a multilateral consultative framework by participating in a meeting on the Strait of Hormuz led by France and the United Kingdom [3]. During this period, President Trump revealed on social media that in March he had directly asked the South Korean president to cooperate on Iran’s denuclearization, but received the reply “No thanks” [2]. Citing this, President Trump ordered a reduction in the scale of U.S.-South Korea joint military exercises and raised the issue of South Korea’s non-cooperation on the Iran conflict [17]. The South Korean government has since maintained its position that no decision has been made on dispatching troops, while reviewing ways to contribute to freedom of navigation and maritime security in the Strait of Hormuz [17].

2. Current Situation

At a press conference on September 17, President Lee Jae-myung stated that while “minimal activities to protect the lives of our citizens and South Korean merchant vessels are necessary,” there would be no troop dispatch that could lead to intervention in war or combat [16][14]. The *Nihon Keizai Shimbun* assessed this as a response to pressure from Washington, while reporting that the possibility of dispatching assets to support freedom of navigation remained open [10]. The *Tehran Times* characterized it as a “decisive stance rejecting Trump’s demand,” citing the spread of anti-war sentiment and strategic prudence in South Korea as the underlying factors [12][20].

When U.S. media reported the statement as a rejection of President Trump’s request, the Blue House immediately moved to control the narrative. A Blue House official stated on September 19, “In yesterday’s press conference, President Lee did not reject President Trump’s request for South Korea’s cooperation regarding the Middle East” [1]. The official added, “The government will continue to review specific ways to contribute, based on its principled position of not intervening in war or combat” [1]. Yonhap News also relayed the Blue House’s explanation that the president’s remarks were not a rejection of Trump’s request [7].

Internally, the government’s working-level procedures appear to be regressing. The National Security Council (NSC) Standing Committee, which met on September 17, removed the Hormuz troop dispatch proposal from its agenda [19]. The committee was initially scheduled to discuss whether to submit a troop dispatch motion to the National Assembly, but the issue was sent back for “reconsideration” due to falling approval ratings and growing public opposition [19]. Around the same time, Foreign Minister Cho Hyun, in a meeting with U.S. Secretary of State Rubio, reaffirmed Seoul’s “willingness to make a substantial contribution alongside the United States and the international community to restore freedom of navigation in the Strait of Hormuz” [16]. A senior Foreign Ministry official explained that the U.S. side did not request a specific form of contribution during the meeting [16].

3. Key Actors and Positions

President Lee Jae-myung and the Blue HousePresident Lee and the Blue House are simultaneously advancing the cause of protecting South Korean nationals and national interests alongside the principle of non-intervention in war. The Blue House has repeatedly emphasized that this principle is not a direct rejection of President Trump’s request, leaving open the possibility that it will continue to review specific contribution plans [1][4]. This is interpreted as an attempt to delay the timing of the decision itself amid the conflicting pressures of domestic anti-war sentiment and the need to manage relations with the United States [19].

The Trump AdministrationThe Trump administration has publicly linked South Korea’s non-cooperation to the reduction of U.S.-South Korea joint military exercises [17][2]. President Trump has further asserted that countries that failed to cooperate in the Iran conflict should compensate the United States for its costs after the war ends [18]. This is seen as an attempt to shift the burden of security costs in the Strait of Hormuz to allies, using the issue as leverage that could affect broader negotiations on defense cost-sharing and investment in the U.S. [9].

South Korean Domestic Public OpinionThe South Korean public is opposed to dispatching troops. In a column for *The Hankyoreh*, Professor Pak No-ja of the University of Oslo criticized the very consideration of a deployment as having “neither justification nor practical benefit,” arguing that such a decision would contradict the current administration’s mandate [15]. Rallies protesting U.S. pressure for troop deployment were held in Seoul, which the *Tehran Times* reported were summarized by the slogan, “This is not our war” [20]. This public sentiment is understood to have directly influenced the NSC Standing Committee’s decision on September 17 to remove the proposal from its agenda [19].

IranIran perceives South Korea’s mere consideration of a troop dispatch as a threat. An Iranian security official warned South Korea not to sacrifice Iran’s interests by cooperating with U.S.-led military operations, and the Islamic Revolutionary Guard Corps (IRGC) has previously targeted vessels in and near the Strait of Hormuz [6]. This provides a compelling practical reason for South Korea to clearly define its area of operations and the nature of its mission before making any deployment decision.

The International CommunityThe international community is divided. The EU has adopted a dual-track approach, joining the economic pressure campaign against Iran while minimizing direct military involvement; France has also refused to participate directly in operations to keep the strait open [9]. For Gulf oil producers such as Saudi Arabia, Qatar, and the UAE, the prolonged war has raised doubts about their ability to fulfill their investment commitments to the United States [5]. The Stockholm International Peace Research Institute (SIPRI) has pointed out that the wording of the Islamabad Memorandum could give Iran leeway to permanently restrict navigation in the Strait of Hormuz, warning that the issue of freedom of navigation could have global repercussions depending on the outcome of a final peace agreement [8].

4. Key Issues

The first issue is defining the line between “non-intervention in war” and a “substantial contribution.” The government’s position is to rule out combat involvement but consider activities such as protecting merchant vessels or supporting freedom of navigation. However, it remains unclear how this line will be drawn when determining the actual format, operational area, and weapon systems for any potential deployment [16][19].

The second issue is that the matter is de facto linked to negotiations on U.S. investment and defense cost-sharing. Since President Trump has publicly raised the demand for postwar compensation from non-cooperating countries, the level of South Korea’s contribution in Hormuz is likely to become a separate variable in future trade negotiations [17][18].

The third issue is the conflict with the domestic political calendar. Rushing a decision on troop deployment amid falling approval ratings would increase the political burden. Therefore, the government has a strong incentive to respond by delaying the timing of an announcement, as seen when the NSC Standing Committee sent the proposal back for reconsideration [19].

The fourth issue is managing relations with Iran. If a decision to deploy troops is made, South Korean assets and nationals could be exposed to direct threats unless accompanied by measures to mitigate the risk of misidentification and targeting, such as separating the operational area from actual combat zones [6].

II. In-Depth Analysis

The Request for Troop Dispatch to the Strait of Hormuz and South Korea’s “Non-Intervention in War” Stance

1. Analysis of Root Causes

The root cause of this issue lies in the fundamentally different interests of the United States and South Korea regarding the conflict with Iran. For President Trump, the war is a test of his campaign promise of “peace through strength” [13]. The Council on Foreign Relations (CFR) has described the failure to achieve either regime change or an end to the war after six months as a situation in which “the United States has no good options” [13]. President Trump has indicated his intention to prolong the war beyond the midterm elections [11]. In this context, contributions of troops and assets from allies serve as a political means to alleviate the domestic controversy over the costs of the war.

For South Korea, by contrast, Iran is not the source of a direct security threat. The Strait of Hormuz is a vital route for oil imports and trade, not a theater of conflict in which South Korea is a direct stakeholder. President Lee’s distinction between “minimal activities to protect the lives of our citizens and South Korean merchant vessels” and “intervention in war or combat” accurately captures this asymmetry [16][14]. The South Korean government’s desired outcome is the functional objective of securing freedom of navigation, not achieving regime change in Iran or advancing U.S. war aims.

The second root cause is South Korea’s domestic political structure. A previous EAI analysis framed this issue as a dynamic in which “three goals—signaling to the United States, securing domestic legitimacy, and managing relations with Iran—are in simultaneous conflict” [3]. It is a zero-sum game: prioritizing any one goal undermines the other two. Strengthening signals to the U.S. clashes with domestic anti-war sentiment. Catering to public opinion fuels dissatisfaction in Washington. And managing relations with Iran weakens the rationale for U.S. pressure. This very structure is the fundamental driver compelling the government to repeatedly make the ‘decision to defer a decision.’

2. Structural Context

Political Structure. Domestic public opinion is clearly tilted against troop deployment. In his *Hankyoreh* column, Professor Pak No-ja described the government’s mere consideration of deployment as “political suicide.” He argued that because the Lee Jae-myung administration’s mandate was rooted in suppressing insurrectionary forces and restoring democratic order, entanglement in U.S.-Israeli military action would constitute a betrayal of the administration’s identity [15]. The *Tehran Times* highlighted the spread of anti-war sentiment by reporting on rallies in Seoul against U.S. pressure, summarizing them with the slogan “This is not our war” [20]. This public pressure has had a tangible impact on government decision-making. On September 17, the NSC Standing Committee removed the troop dispatch proposal from its agenda—a proposal that was initially meant to be discussed up to the point of submission to the National Assembly—citing falling approval ratings as the reason [19]. This indicates that political costs are taking precedence over security and diplomatic considerations.

Economic Structure. This issue is not limited to troop deployment. When ordering the reduction of U.S.-South Korea joint exercises, President Trump also cited South Korea’s non-cooperation on Iran [17][2]. He later demanded compensation for securing the Strait of Hormuz, adding pressure by stating that Seoul “gave no help at all” [18]. The deployment issue is thus linked to the separate tracks of negotiations on defense cost-sharing and investment in the U.S. The Peterson Institute for International Economics (PIIE) has analyzed that the Iran war is undermining the ability of Saudi Arabia, Qatar, and the UAE to fulfill their investment pledges to the U.S. [5]. This suggests that as expected funds from Gulf oil producers diminish, pressure on other allies like South Korea to contribute could increase. For the South Korean government, refusing to dispatch troops carries the risk of repercussions in investment and trade negotiations with the United States.

Security Structure. Iran perceives South Korea’s consideration of a troop deployment as a tangible threat. According to an EAI analysis, an Iranian security official specifically warned South Korea not to sacrifice Iran’s interests, and the IRGC has in fact targeted six vessels near the Strait of Hormuz [6]. This implies that even if South Korea frames its involvement as “non-combat support,” Iran could deem it an act of war and subject it to physical retaliation. Simultaneously, SIPRI has noted that the wording of the Islamabad Memorandum could be interpreted as de facto granting Iran the authority to restrict passage through the Strait of Hormuz, warning that such a development could have repercussions for the principle of freedom of navigation far beyond the Gulf region [8]. The security structure facing South Korea is thus not merely about whether to dispatch troops; it is more fundamental, in that the final terms of a U.S.-Iran agreement could dictate the future of South Korea’s own energy supply routes.

3. Historical Precedents and Comparative Cases

South Korea’s deployment dilemma is not unprecedented. During the dispatch of the Zaytun Division to Iraq and troops to Afghanistan, the government sought a compromise between U.S. requests and domestic anti-war sentiment by framing its contribution as “non-combat support.” The rear-echelon support options the government is currently considering, such as dispatching a logistics support ship and maritime patrol aircraft, follow the same logic [9]. A crucial difference from past cases, however, is that this time a belligerent party, Iran, has explicitly cited potential South Korean participation as grounds for a targeting threat [6]. During the Iraq and Afghanistan deployments, no such specific and public warning of retaliation from a third party was ever issued.

Internationally, the responses of the European Union and France offer a useful comparison. The EU has pursued a dual-track policy, joining the U.S.-led economic pressure campaign against Iran while minimizing direct military involvement, and France has likewise refused to participate directly in operations to keep the strait open [9]. This approach is effectively aligned with South Korea’s principle of limiting its role to “non-combat and strait stabilization missions.” This suggests that avoiding direct military intervention in the Iran conflict is not an exception but a common pattern among traditional U.S. allies. President Trump’s tactic of publicly citing South Korea’s refusal with the phrase “No thanks” [2] is also consistent with his administration’s distinctive negotiating style of publicly shaming allies for passive cooperation to intensify pressure.

4. Key Variables Shaping Future Developments

The first variable is the trajectory of the U.S.-Iran stalemate that has unraveled since the expiration of the Islamabad Memorandum. Since the memorandum expired on August 17, Iran has reverted to a more aggressive posture [3][6], and the U.S. Navy has publicly mentioned the possibility of retaliatory strikes against the IRGC for targeting ships [6]. The level of physical risk South Korea would have to assume depends on whether this low-intensity conflict escalates or enters another truce phase through third-party mediation by countries like Oman.

The second variable is the domestic political calendar and presidential approval ratings. Given that falling approval ratings and worsening public opinion were the decisive factors in the NSC’s decision to remove the deployment proposal from its agenda [19], future trends in President Lee’s approval ratings and the level of organized anti-war sentiment are likely to continue pushing the government to delay its decision.

The third variable is the extent of U.S. patience and the degree to which it links the issue to trade and defense cost-sharing negotiations. Given President Trump’s precedent of reducing U.S.-South Korea joint exercises and publicly demanding compensation for securing the Strait of Hormuz [17][18], the longer South Korea defers its decision, the more likely it is that U.S. demands for concessions in investment and tariff negotiations will become more concrete. How skillfully the government manages the timing and format of its participation at the intersection of these three variables will likely determine the ultimate outcome of this issue.