The Strait of Hormuz Crisis and NATO's Dilemma of Non-Intervention: Implications and Policy Options for South Korea

Executive Summary

While convening a video conference on August 19, NATO found a compromise between U.S. pressure for intervention and European aversion to escalation by framing the effort as “voluntary contributions by interested member states, not an alliance mission.” This formula sets a precedent for allowing differentiated responses within the alliance framework, where directly threatened members like Türkiye can respond actively while the majority of Western European nations limit their involvement. Given its bilateral alliance structure, South Korea must proactively establish such buffers for itself. In preparation for future U.S. requests for contributions, Seoul needs to pre-define the line between participation in an “alliance mission” and offering “individual, limited contributions.” Simultaneously, the de facto establishment of Iran’s unilateral transit system as the standard route following the expiration of the Islamabad Memorandum poses a direct risk to South Korea’s energy procurement. The high oil price environment, with crude in the $88-95 per barrel range, is expected to persist for the foreseeable time amid recurring cycles of negotiation and tension. Therefore, the most realistic course of action at this juncture is to pursue a dual-track response: proactively establishing a security framework on the one hand, and implementing a resilient energy procurement strategy on the other.

I. Situational Analysis

The Strait of Hormuz Crisis and NATO's Dilemma of “Alliance Non-Intervention”: A Situational Analysis

1. Background and Timeline

The starting point of the current crisis was the U.S.-Israeli airstrike on Iran on February 28, 2026 [8][10]. The war, which lasted over four months, entered a temporary resolution phase with the signing of the “Islamabad Memorandum” on June 17 [6][10]. Immediately after the signing, President Trump confidently declared the strait’s reopening, stating, “Ships of the world, start your engines” [10]. However, the memorandum's wording was controversial from the outset. SIPRI pointed out that its provisions gave Iran leeway to perpetuate its restrictions on navigation in the Strait of Hormuz in a final peace treaty [6]. Indeed, a ceasefire reached in April quickly collapsed after attacks resumed within the strait [10].

The memorandum expired on August 17 [5][10]. Iran immediately shifted to a more aggressive policy stance, and the United States ruled out an extension of the temporary agreement [5][10]. At this juncture, the Financial Times reported that Iranian-linked figures had considered the possibility of striking U.S. military bases in Europe, such as those in Bulgaria and Cyprus, following President Trump’s refusal to negotiate [7][9]. The possibility of striking undersea infrastructure near the Strait of Hormuz was also mentioned [7]. In response, NATO asserted that its deterrence and defense posture was robust, citing its track record of intercepting four Iranian ballistic missiles fired toward Türkiye [9][11][12][14]. Bulgaria enhanced security at its Bezmer Air Base, and Denmark placed an order with defense contractor Terma for a counter-drone command and control system [12][14].

2. Current Situation

On August 19, Supreme Headquarters Allied Powers Europe (SHAPE), under the command of NATO Supreme Allied Commander General Alexus Grynkewich of the U.S. Air Force, convened a video conference for defense ministers of interested member states [1][4]. A SHAPE spokesperson clarified to Reuters that the meeting was to coordinate contributions from member states to support freedom of navigation in the Strait of Hormuz, drawing a clear line by stating it was “not a NATO mission” [1][4]. Al Jazeera reported on this development under the headline, “Europe hesitates as U.S. pushes for Hormuz naval mission,” noting that European allies were torn between U.S. requests for intervention and their desire to avoid escalation [14].

Simultaneously, efforts to de-escalate tensions are underway through diplomatic channels. Omani Foreign Minister Badr Albusaidi and Iranian Foreign Minister Abbas Araghchi held a phone call to seek a “practical understanding” on transit through the strait [13]. Türkiye and Iran also discussed efforts to keep the strait open and ways to sustain the U.S.-Iran ceasefire [15]. Since the expiration of the Islamabad Memorandum, vessels transiting the strait appear to be using the unilateral passage system established by Iran as the de facto standard route [10].

3. Key Actors and Positions

NATO Secretariat/SHAPE: Is adopting a dual approach, avoiding an official alliance mission while providing a coordination platform for interested nations [1][4]. This can be interpreted as institutional prudence aimed at avoiding disputes over burden-sharing among member states and the risk of entanglement in a wider conflict, which would arise from committing alliance resources to an issue not meeting the threshold for invoking the collective defense clause (Article 5). At the same time, it is repeatedly messaging that its deterrence and defense posture is “strong and effective,” highlighting its success in air defense over Türkiye [9][11][12][14].

United States: The Trump administration, which has made low oil prices a key objective of its economic war against Iran, is demanding multinational contributions to secure freedom of navigation in the strait [5][14]. However, due to physical constraints, namely the depletion of its own interceptor missile stockpiles (at least a 38% reduction for THAAD and up to a 65% reduction for Patriot), it appears to be seeking to distribute the burden among allies rather than pursuing military escalation [8].

European NATO Members: While countries mentioned as potential Iranian targets, such as Bulgaria and Greece, have moved to strengthen their defensive postures [12][14], their involvement in a strait mission is limited to weighing individual, voluntary contributions. The “hesitation of Europe” noted by Al Jazeera reflects a calculation to avoid becoming a direct party to a conflict with Iran through an alliance-level intervention, even as they bear the energy and security risks [14].

Iran: Has maintained its position that it will keep the strait closed without a U.S. military withdrawal and the lifting of sanctions [2]. At the same time, there are signs that it is using the threat of a potential strike on U.S. bases in Europe as leverage to press for a resumption of negotiations [7][8][9].

Oman and Türkiye: Are attempting to de-escalate tensions between Iran and the U.S. as regional mediation channels [13][15]. However, reports of President Trump's threat to bomb Oman are acting as a variable that undermines the credibility of this sole mediation channel [10][14].

4. Key Issues

The first issue is the legal and political scope of NATO's intervention. The recent video conference took the form of a voluntary consultative body of “interested member states,” not an alliance mission [1][4]. This can be seen as a clear line-drawing exercise to avoid taking on a direct military confrontation with Iran at an organizational level in a situation that does not meet the criteria for invoking Article 5 collective defense.

The second issue is the legal legacy of the Islamabad Memorandum. Although the memorandum has expired, the spirit of the navigation restriction clause pointed out by SIPRI continues to maintain de facto normative force in the form of Iran's unilateral transit system [6][10]. Whether this system will be transformed into a multilateral maritime safety regime or solidify as Iran's permanent leverage is a watershed for future negotiations.

The third issue is the location of potential escalation triggers. The rumored consideration of strikes on U.S. military bases in Europe by Iran is not yet at the implementation stage, but it has for the first time concretized the possibility that NATO member territory could be drawn into the ripple effects of the U.S.-Iran conflict [7][8][9]. The cautious stance of European countries, willing to engage with the Hormuz issue only conditionally, can be read as a preemptive defensive line against this escalation risk.

II. In-Depth Analysis

The Strait of Hormuz Crisis and NATO's Dilemma of “Alliance Non-Intervention”: An In-Depth Analysis

1. Analysis of Root Causes

The root cause of the current situation lies in the design flaws of the Islamabad Memorandum itself. SIPRI noted that a key provision of the memorandum contained language that would allow “the United States to permit Iran to include in a final peace treaty the authority to permanently restrict freedom of navigation in the Strait of Hormuz” [6]. A temporary document intended to secure a ceasefire thus left open the possibility of ceding authority over an international public good—freedom of navigation—to Iran. This ambiguity provided both negotiating parties, the U.S. and Iran, with victory narratives for their domestic audiences, but it left third parties like the European allies to bear the full weight of the legal vacuum after the memorandum's expiration.

A deeper cause is the shift in U.S. security interests. A previous EAI analysis diagnosed that “the United States has lost its direct economic incentive to protect the strait due to increased energy self-sufficiency, yet it remains in a structural dilemma where the shock of an oil price surge from a blockade still translates into domestic political burdens” [2]. Washington is in an awkward position where its urgent economic reasons to protect the strait have diminished, yet it must still bear the political costs of a spike in oil prices. This ambiguity has led the U.S. to seek a compromise, requesting voluntary contributions from “interested allies” instead of a full-fledged NATO mission [1][4].

Iran's fundamental motivation is clear. An EAI analysis assessed that Iran “defines control over the strait as an asymmetric lever directly linked to regime survival” [2]. Outmatched by the U.S. and Israel in conventional military power, Iran uses its ability to blockade the strait as its only card of equal value at the negotiating table. As long as there is no economic incentive to relinquish this card, tensions are structurally bound to recur, regardless of the existence of any memorandum.

2. Structural Context

Security Structure: The Threshold Effect of NATO's Article 5

The dual nature of NATO's response stems from the activation requirements of its collective defense clause. Iranian ballistic missiles aimed at Turkish territory were intercepted four times, and based on this, NATO declared its “deterrence and defense posture is strong and effective” [9][11][12][14]. This unified response was possible because it concerned a direct threat to a member's territory, a clear trigger for Article 5. However, freedom of navigation in the Strait of Hormuz falls into a separate legal category—the protection of international sea lanes, not the defense of member territory. The SHAPE spokesperson's insistence that the video conference was “not a NATO mission” [1][4] is an act of institutional self-discipline to avoid crossing this threshold. Committing alliance assets would simultaneously trigger negotiations on burden-sharing and risks of entanglement in a wider conflict. Therefore, the NATO Secretariat opted for a structure where it only provides a coordination platform, leaving the actual decision to deploy troops or ships to the sovereign choice of individual member states.

Political Structure: Diverging Temperatures within Europe

Al Jazeera summarized this situation with the headline, “Europe hesitates as U.S. pushes for Hormuz naval mission” [14]. This phrase encapsulates the divergent perspectives of the United States and Europe. While the U.S. has become less dependent on oil imports, many European countries remain exposed to Gulf energy supplies and maritime trade with Asia. Nevertheless, European nations are reluctant to step forward because if they deploy their own ships and personnel to the conflict zone, they would have to bear the risk of becoming targets for Iranian retaliation alone. Indeed, figures close to the Iranian regime were reported to have considered striking U.S. military bases in Europe, such as in Bulgaria and Cyprus, immediately after President Trump's refusal to negotiate [7][9]. Bulgaria has reinforced security at its Bezmer Air Base, and a previous EAI analysis noted that Greece considered relocating Patriot missiles to Crete [8]. In other words, Europe is already within Iran's potential retaliation zone regardless of its intervention in the strait, creating a paradoxical structure where this very fact reinforces caution.

Economic Structure: Stockpile Depletion and Constraints on Escalation Capacity

The fact that America's own capacity for escalation is physically limited is another structural variable. According to an EAI analysis, the prolonged conflict with Iran has led to a “reduction in U.S. interceptor missile stockpiles of at least 38% for THAAD and up to 65% for Patriot” [8]. The Atlantic Council has presented similar depletion rates, projecting that replenishment could take years due to production bottlenecks for components [8]. This inventory constraint acts as a double pressure: it strengthens the White House's incentive to draw on the assets of NATO allies for the Hormuz mission, while simultaneously making European countries reluctant to see their own air defense assets used to fill America's inventory gap.

3. Historical Precedents and Comparative Cases

The closest precedent to the current situation is the U.S. operation to reflag Kuwaiti oil tankers during the 1987-88 “Tanker War.” At that time, the U.S. secured a pretext for intervention by escorting Kuwaiti tankers flying the American flag amidst the Iran-Iraq War, but this was a unilateral U.S. decision in which NATO was not involved. What makes the current case different is that the U.S., instead of intervening unilaterally, has sought to coordinate “voluntary contributions” from allies from the outset. This can be seen as a result of the accumulated fatigue from unilateral interventions in Iraq and Afghanistan within the U.S., combined with the aforementioned constraints on interceptor missile stockpiles.

The U.S.-led International Maritime Security Construct (IMSC), formed during the 2019 Hormuz tanker attack crisis, exhibited a similar structure. Then, too, a “coalition of the willing” approach was adopted instead of a NATO mission, and some major European countries like France and Germany refused to participate, forming their own separate European-led maritime surveillance mission (EMASoH). The NATO Secretariat's clear statement that the recent video conference was “not a NATO mission” [1][4] can be interpreted as a reflection of the lessons learned from 2019. In other words, by not using the NATO brand, it preemptively prevents defections like the French pursuit of an independent course and opts for a lowest-common-denominator approach that loosely binds only those countries willing to participate.

Efforts to keep the strait open through the Turkey-Iran channel [15] and Oman's mediation attempts [13] are also patterns that have been repeated in past Gulf crises. Oman is once again reprising its role as the region's sole buffer state, having maintained dialogue channels with both the U.S. and Iran since the 1980s. However, as an EAI analysis points out, President Trump's threat to bomb Oman is shaking the foundations of this unique mediation channel [10], which is a new risk factor that distinguishes the current situation from past cases.

4. Key Variables Shaping Developments

The first variable is whether a multilateral norm will emerge to replace the legal vacuum left by the Islamabad Memorandum. The fact that Iran's unilateral transit system is being used as the de facto standard route by “all 11 transiting vessels as of August 11” [10] shows that this system is solidifying into an actual practice, regardless of its legal status. Whether this practice transitions into a multilateral maritime safety management regime or becomes a permanent unilateral power for Iran will determine the level of participation from European allies in the future.

The second variable is the survival of the Omani and Turkish mediation channels. While the phone call between the Omani and Iranian foreign ministers [13] and the consultations between Türkiye and Iran [15] are ongoing, these channels could collapse if President Trump's threat to bomb Oman [10] reoccurs. As long as the mediation channels remain viable, European countries have a reason to postpone military contributions and wait for a diplomatic solution. If the channels break down, their room to maneuver in response to U.S. pressure will narrow.

The third variable is whether Iran's threats of retaliation within Europe materialize. If the rumored consideration of strikes on U.S. military bases in Bulgaria and Cyprus [7][9] translates into actual action, NATO will cross the Article 5 threshold, rendering the current compromise of “alliance non-intervention” meaningless. Conversely, if this threat remains at the level of a deterrent display, Europe is likely to maintain its current approach of selective, voluntary participation for a considerable period.

The fourth variable is the speed at which the U.S. replenishes its interceptor missile stockpiles [8]. As long as these inventory constraints persist, the U.S. will have an incentive to continue requesting contributions of air defense assets from its European allies. This could have ripple effects beyond the Hormuz mission, influencing future discussions on air defense budget allocations and the development of indigenous interceptor systems among NATO members.