The U.S. Carrier Gap in the Western Pacific and Intensifying Military Competition in the Taiwan Strait and South China Sea: Structural Causes and Implications for the Korean Peninsula

Executive Summary

As the war in Iran dragged on, the USS Abraham Lincoln's deployment was extended to over 260 consecutive days. In response, the U.S. Navy redeployed the Yokosuka-based USS George Washington to the Middle East, creating a complete absence of carrier presence—a 'carrier gap'—in the Western Pacific. During this period, Taiwan conducted its Han Kuang exercises. However, instead of its usual large-scale counter-drills, China responded with silence and brief, derogatory remarks, a pattern that suggests a weaponization of unpredictability. Meanwhile, Chinese official vessel activity around Taiwan reached 118 instances in August, setting a record high for the third consecutive month. A joint exercise between the Indonesian and Chinese navies put Jakarta's principle of non-alignment to a practical test, demonstrating that its 'conditioned hedging'—rooted in the structure of its nickel industry—is advancing to a phase of institutionalization, marked by a 2+2 dialogue. The fundamental cause of this situation is the structural limitation of the U.S. Navy's 11-carrier force structure, which complicates simultaneous responses in two major theaters. The trend of a lowering threshold for gray-zone activities in the Taiwan Strait and South China Sea is likely to persist for a significant period, regardless of when the war in Iran concludes. South Korea must re-examine its response strategies in discussions on U.S. extended deterrence and trilateral cooperation with the U.S. and Japan, taking into account these shifts in the regional deterrence posture and the diverging hedging strategies among ASEAN countries.

I. Analysis of the Current Situation

The U.S. Carrier Gap in the Western Pacific and Intensifying Military Competition in the Taiwan Strait and South China Sea: An Analysis of the Current Situation

1. Background and Developments

The war in Iran, lasting longer than anticipated, has disrupted the U.S. Navy's carrier deployment plans. The USS Abraham Lincoln's deployment was extended far beyond its originally scheduled return in May, marking a record of over 260 consecutive days of at-sea operations [5]. The deteriorating mental health of the crew and logistical problems were repeatedly reported by local media [5][8]. To alleviate this situation, the U.S. Navy redeployed the USS George Washington from its base in Yokosuka, Japan, to the Middle East [8]. After completing a port call in Da Nang, Vietnam, the George Washington transited the Singapore and Malacca Straits, heading for the Indian Ocean [5]. It arrived in the Middle East and commenced operations on August 19 [8]. This move created a complete vacuum of U.S. aircraft carrier presence in the Western Pacific [5][8].

During the same period in August, Taiwan conducted its ten-day Han Kuang exercises, which simulated an all-out war with Beijing. It was a large-scale drill that included scenarios such as a blockade, attacks on critical infrastructure, and an internet blackout [2]. A notable shift occurred in China's response to these exercises. Beijing refrained from making any official comments until the final day of the drills. The subsequent statement was merely a brief, derogatory remark, dismissing the exercise as a "wasteful show" [2]. This response marked a departure from Beijing's previous pattern of conducting large-scale counter-drills [2]. It can be interpreted as a tactical shift toward making the timing and intensity of its reactions unpredictable.

During the same period, the Indonesian Navy frigate KRI I Gusti Ngurah Rai conducted a joint exercise with a People's Liberation Army (PLA) Navy vessel in the waters east of Taiwan [2][10]. The constitutional foundation of Indonesia's foreign policy is the principle of 'free and active' (bebas dan aktif) non-alignment [2][10]. Since his inauguration, President Prabowo Subianto has repeatedly emphasized this principle, vowing to maintain friendly relations with both China and the United States [2][10]. This principle was put to a practical test on August 19. Taiwan's defense and foreign affairs authorities immediately protested, demanding an explanation from Jakarta on the nature and circumstances of the exercise [10]. The Indonesian government defined it as a routine 'passing exercise' and stressed that it involved no combat elements [10].

2. Current Situation

According to data from Taiwan's Ministry of National Defense, official Chinese vessels, including coast guard and survey ships, were detected 118 times in the waters around Taiwan during the first 24 days of August. This figure surpasses the 117 instances in July and 111 in June, setting a new record high since Taiwan began publicizing these statistics in July 2024 [13]. According to SCMP data, the previous monthly high before June was 50 in April 2025. Setting a new record for three consecutive months represents a trend that significantly exceeds typical fluctuations [13]. This increase coincides with the period when Beijing intensified its law enforcement and survey activities following the announcement of maritime boundary negotiations between Tokyo and Manila [13].

Cooperation between Indonesia and China has also moved toward institutionalization following the joint exercise. The bilateral 2+2 dialogue (between foreign and defense ministers) held in Jakarta on August 21, 2026, was the second such meeting, following the inaugural one in April 2025 [11]. The Diplomat has pointed out that the significance of this dialogue should not be assessed on its symbolic value alone [11]. EAI's analysis connects these moves by Indonesia to its structure of dependency on China, which is rooted in its nickel downstreaming policy. This is assessed as follows: "The Prabowo government is pursuing a dual strategy of maximizing its practical interests while maintaining the rhetoric of non-alignment, and this should be viewed as conditioned hedging rather than an ideological shift" [10].

Meanwhile, the repercussions of the U.S. carrier absence are not confined to the Western Pacific. The ROK-U.S. Marine Corps' Ssangyong exercise was canceled, citing constraints on force availability due to the war in Iran [1][7][9]. This decision came shortly after the Ulchi Freedom Shield exercise was shortened from 11 to 5 days [9]. Arab News described the situation by stating that "the war with Iran is testing the limits of the U.S. Navy," and pointed out that this coincided with China's intensified assertiveness [8]. The Indian media outlet Mint highlighted the Trump administration's "inconsistent geopolitical stance" [8]. In the Middle East, SIPRI warned that the language of the provisional U.S.-Iran agreement (the Islamabad Memorandum of Understanding) could result in permanent restrictions on freedom of navigation in the Strait of Hormuz [3]. Amid these developments, China was seen securing a pretext for involvement in Middle Eastern affairs, issuing a joint statement with Jordan that called for the normalization of the situation in the Strait of Hormuz and the maintenance of the ceasefire [4].

3. Key Actors and Positions

Chinais adopting tactics to exploit the carrier gap while staying below the threshold of escalation. While increasing its vessel activity around Taiwan to record levels [13], its official response to the Han Kuang exercises was limited to a restrained commentary [2]. This approach is designed to complicate the response calculations of Taiwan and the United States by reducing predictability. At the same time, China is testing its strategic reach toward the Middle East through a 6,000-kilometer long-range deployment exercise with Egypt [12], concurrently expanding its influence on multiple fronts.

Taiwanconducted realistic drills through its Han Kuang exercises to prepare for scenarios including blockades, attacks on critical infrastructure, and communications blackouts [2]. However, it faced an unexpected variable in the form of the joint Indonesia-China exercise. Its immediate demand for an explanation from Jakarta was a measure that reflected concerns about its own security environment [10].

Indonesiaappears to be pursuing its practical interests by balancing between two pillars: its principle of non-alignment and its economic dependence on China, which is mediated by its nickel supply chain [2][10][11]. The institutionalization of the 2+2 dialogue suggests that this relationship is not based on a one-off exercise but has entered a sustained trajectory [11].

United Stateshas encountered the structural constraint of responding simultaneously to a two-theater scenario. The extended deployment of the USS Lincoln and the redeployment of the USS George Washington to the Middle East were decisions stemming from the physical limits of available forces rather than a deliberate downplaying of Asia's importance [5][8]. This constraint also led to the scaling back of combined ROK-U.S. military exercises [1][7][9].

South Koreais directly experiencing the vulnerability of its long-standing practice of depending on the U.S. force deployment schedule for its security. The cancellation of the Ssangyong exercise and the scaling back of the Ulchi Freedom Shield exercise have the potential to spark debates over the credibility of the alliance [1][7][9].

4. Key Issues

First, a key question is whether the carrier gap is a temporary incident or a recurring structural pattern. The constraint that U.S. carrier forces are insufficient to manage two major theaters simultaneously is likely to manifest again in similar forms even after the situation in Iran is resolved.

Second is the question of whether China's unpredictable response tactics will become a new standard for gray-zone provocations. The combination of record-level vessel activity and restrained official commentary places a new burden on Taiwan's alert and response systems [2][13].

Third, the regional security architecture will be shaped by whether hedging within ASEAN remains confined to Indonesia or spreads to other South China Sea claimant states, such as the Philippines and Vietnam. This potential spread is more likely to occur at a fragmented pace, varying according to each country's specific structure of economic dependence on China, rather than happening uniformly [10].

Fourth, within the context of the ROK-U.S. alliance, the uncertainty surrounding U.S. force deployments has the potential to escalate into a broader debate on the credibility of extended deterrence. It is necessary to assess whether the cancellation of the Ssangyong exercise was a one-off adjustment or a harbinger of future reductions in combined military exercises [1][7][9].

II. In-Depth Analysis

The U.S. Carrier Gap in the Western Pacific and Intensifying Military Competition in the Taiwan Strait and South China Sea: An In-Depth Analysis

1. Analysis of Root Causes

The ostensible cause of the current situation is the prolonged war in Iran. However, a more fundamental cause is the size of the U.S. Navy's aircraft carrier fleet. The U.S. Navy nominally maintains a force of 11 carriers, a size that makes it difficult to maintain a strong posture in two major theaters simultaneously [5][8]. The USS Abraham Lincoln, tied down in the Middle East, set a record of over 260 consecutive days of at-sea operations [5]. The deteriorating mental health of its crew and logistical problems were repeatedly reported in local media [5][8]. The only way to resolve this issue was to draw forces from another theater, and the USS George Washington, stationed in the Western Pacific, was chosen for this purpose [8].

This structural issue should be viewed less as a policy choice by the Trump administration and more as a case of the post-Cold War downsized fleet exposing its limitations in the face of two simultaneous crises. The Associated Press described the situation by stating, "Trump pulls last US aircraft carrier from Asia as he focuses on Iran, Western Hemisphere" [5]. Arab News, however, framed it as "the war with Iran is testing the limits of the U.S. Navy" [8]. The perspectives of both media outlets converge on the point that this is a matter of physical limitations rather than deliberate neglect. This reveals the essence of the dilemma the United States faces in the military dimension of its strategic competition with China. Lacking a fleet large enough to project strong deterrence simultaneously in two theaters—the Middle East and the Indo-Pacific—the structure is such that a prolonged crisis in one automatically creates a vulnerability in the other.

The shift in China's response can also be interpreted as a result of its learning from this structural gap. In response to Taiwan's Han Kuang exercises, Beijing opted for silence and brief, derogatory remarks instead of its previous large-scale counter-drills [2]. This is a tactic designed to make the timing and intensity of its reaction unpredictable. A method that makes a state's response patterns unforeseeable has the effect of eroding the credibility of deterrence. As the U.S. physical gap and China's cultivation of psychological uncertainty work in tandem, the structural costs of managing tensions in the Taiwan Strait are rising.

2. Structural Context

Security Structure: The Two-Theater Dilemma and Gray-Zone Expansion

Data from Taiwan's Ministry of National Defense illustrates this structural problem numerically. In the first 24 days of August, official Chinese vessels were detected 118 times around Taiwan. This figure surpasses the 117 instances in July and 111 in June, marking the highest record since July 2024 [13]. The previous monthly high before June was just 50, in April 2025 [13]. Setting a new record for three consecutive months clearly exceeds the range of normal fluctuation. The timing of this increased activity coincides with the announcement of maritime boundary negotiations between Tokyo and Manila [13]. In other words, China's gray-zone activities are not confined to the Taiwan issue but are expanding in tandem with broader regional boundary delimitation conflicts across the East and South China Seas.

This trend is directly linked to 'changes in the regional deterrence posture,' a key point to monitor in the U.S.-China strategic competition. Deterrence functions when an adversary can predict the costs of a provocation. When the physical absence of a U.S. carrier is combined with the unpredictability of China's response, the result is a lowered threshold for gray-zone activities. In fact, China also conducted a 6,000-kilometer long-range power projection exercise with Egypt [12]. This serves as a test of its long-distance operational capabilities, mediated through its involvement in Middle Eastern affairs, and provides evidence of power projection ambitions that are not confined to the Western Pacific.

Political and Economic Structure: Conditioned Hedging in ASEAN

Indonesia's actions cannot be explained by the security structure alone. The Prabowo government's principle of 'free and active' non-alignment has a constitutional basis [2][10]. However, the practical center of gravity for this principle lies in the country's structure of dependency on China in its nickel downstreaming policy. Indonesia and China held a 2+2 dialogue in Jakarta on August 21, 2026, the second such meeting since the first in April 2025 [11]. The Diplomat has noted that the significance of this dialogue should not be judged on its symbolic value alone [11]. This indicates the confirmation of a structure in which security cooperation and economic dependence are deepening simultaneously.

The Indonesian government defined the joint exercise in the waters east of Taiwan as a routine 'passing exercise,' stressing that it had no combat elements [10]. However, the very choice of timing and location was a signal that caused concern in Taiwan [10]. This can be characterized not as an ideological shift, but as a dual strategy to maximize practical interests—that is, conditioned hedging. The 'condition' in this hedging is the economic variable of the nickel supply chain. Therefore, it is unlikely that this pattern will spread uniformly to other South China Sea claimant states, such as the Philippines and Vietnam, because each country differs in its structure of economic dependence on China and in its status as a direct party to territorial disputes.

Alliance Structure: Fissures in the U.S.-Dependent Posture

This gap also had repercussions for the ROK-U.S. alliance's training schedule. The United States canceled the bilateral Ssangyong exercise, citing force constraints related to the war in Iran [1][7][9]. The Ulchi Freedom Shield exercise was also shortened from 11 to 5 days [9]. This exposes the structural vulnerability of the long-standing practice of relying on the U.S. force deployment schedule for security within the framework of alliances and multilateral security. While the reduction or cancellation of exercises does not immediately lead to a weakening of deterrence, if the U.S. burden of managing two theaters becomes a permanent feature, combined ROK-U.S. exercises could also be subject to repeated adjustments.

3. Historical Precedents and Comparison with Similar Cases

The U.S. Navy's shortage of aircraft carrier capacity is not a new problem. During the Cold War, the Navy operated a fleet of around 15 large carriers, giving it the capacity to dedicate forces to both the Atlantic and Pacific theaters. Since the end of the Cold War, the fleet has been downsized, and the current incident has reconfirmed the structural problem that the present 11-carrier force cannot simultaneously handle two high-intensity conflicts. A similar pattern was seen in 2019–2020, when heightened tensions in the Middle East tied down carrier forces in the Gulf region for a prolonged period, resulting in a deployment gap in the Western Pacific. The current case is a recurrence of this pattern, but in an intensified form, as the duration of the gap has extended to a record 260 days [5].

There is also a precedent for the shift in China's response tactics. Following the 2022 visit to Taiwan by then-U.S. House Speaker Nancy Pelosi, China immediately retaliated with large-scale encirclement drills. This stands in contrast to its response of silence and brief derogatory remarks to the recent Han Kuang exercises [2]. This suggests that on the Taiwan issue, China is adjusting its tactics from 'immediate, large-scale counter-responses' to the 'normalization of unpredictable, low-intensity pressure.' The fact that official Chinese vessel activity around Taiwan set new records for three consecutive months is also consistent with this strategy of low-intensity, constant pressure [13].

Among ASEAN countries, Indonesia's hedging trajectory is notable in its contrast with the Philippines' closer alignment with the United States. Since 2023, the Philippines, as a claimant state in the South China Sea disputes, has strengthened its security cooperation with the U.S. In contrast, Indonesia, which is not a direct party to the territorial disputes, has taken the opposite path of expanding cooperation with China, mediated by its nickel supply chain. This is an extension of the established pattern of ASEAN not converging on a single, unified policy toward China, but rather exhibiting divergent responses based on the individual economic interests of its member states.

4. Key Variables Shaping Future Developments

The first variable is the timing of the end of the war in Iran and the schedule for the return of the U.S. aircraft carrier. The fact that the U.S. Department of Defense has not disclosed a timeline for deploying replacement forces is in itself a source of uncertainty. While end-of-war negotiations are in progress following the signing of the Islamabad Memorandum of Understanding between Iran and the United States, the agreement is assessed as fragile [3]. With the possibility being raised that a final peace treaty could include a clause restricting freedom of navigation in the Strait of Hormuz, any delay in stabilizing the situation in the Middle East will inevitably prolong the carrier gap in the Western Pacific [3]. There are also local reports that Iran is unable to import sufficient oil due to the U.S. naval blockade [14]. This suggests that Iran retains an incentive to negotiate, but it also highlights the fluidity of the situation.

The second variable is whether China's gray-zone activities will cross a critical threshold. While the setting of new records for official vessel activity around Taiwan for three consecutive months demonstrates a pattern of normalized pressure [13], whether this will lead to an actual blockade or an armed conflict is a separate question. As long as the catalyst of maritime boundary negotiations between Tokyo and Manila remains a factor, this pressure is likely to continue on a gradual upward trajectory [13].

The third variable is the potential for divergence in the pace of hedging among ASEAN countries. The future trajectory of dynamics in the South China Sea will depend on whether Indonesia's example spreads to countries like the Philippines and Vietnam, or whether it remains an exception confined by the specific condition of its nickel supply chain. The pace of institutionalization of the China-Indonesia 2+2 dialogue will serve as an indicator for gauging this potential spread [11].

The fourth variable is whether the reduction in combined ROK-U.S. military exercises will be a one-off adjustment or will solidify into a structural pattern driven by the permanent nature of the U.S. two-theater burden. If the cancellation of the Ssangyong exercise and the scaling back of Ulchi Freedom Shield are products of the specific circumstances of the war in Iran, they will likely be restored to their normal scale once the war concludes [1][7][9]. However, as long as the structural limitations of the U.S. fleet size remain unresolved, similar adjustments are likely to be repeated in future crisis scenarios.