Where Aircraft Carriers Leave, a Tighter Net Forms: The Indo-Pacific Kill Web and Divergent Agendas in US-ROK and US-Japan-Australia Exercises
Executive Summary
As the aircraft carrier gap stemming from the Middle East, the shortening of US-ROK joint exercises, and the expansion of US-Japan-Australia exercises overlap, there are clear signs that the defense posture in the Indo-Pacific region is being reorganized from 'platform-centric' to 'network-centric.' Although the 'Kill Web' concept proposed by the Commander of US Forces Korea (USFK) has not yet been finalized in official policy documents, it is supported by his written testimony stating that the United States will support South Korea with 'critical but more limited capabilities,' as well as the expanded budgets for CJADC2 and Project Maven. Due to its defense structure tailored specifically to North Korea, South Korea's transition to connecting with the regional network is bound to be slower than Japan's, a disparity manifested in the asymmetry between the scaling back of US-ROK exercises and the expansion of US-Japan-Australia exercises. The gap between the president's announcement of exercise adjustments through personal channels and the institutional messaging of the command and the Department of Defense moving at different speeds suggests that alliance adjustments remain at the level of signaling rather than policy. If the depletion of aircraft carrier capabilities in the Middle East is prolonged, the gap in the Western Pacific deterrence posture and the pressure to readjust roles among allies are expected to persist for the time being.
I. Analysis of the Current Issue
Why Did the Korean Peninsula Training Grounds Shrink While the Western Pacific Waters Emptied?
What Becomes Visible When the Map Is Turned Upside Down
In November 2025, an article posted on the website of the Commander of US Forces Korea (USFK) caught people's attention. Titled 'East-Up Map,' it argued that rotating the map 90 degrees to place east at the top reveals the advantages of the 'strategic triangle' connecting South Korea, Japan, and the Philippines [deleted source]. In this article, USFK Commander Brunson divided their roles, designating South Korea as the 'central depth,' Japan as 'technology and maritime reach,' and the Philippines as 'access to southern sea lines of communication' [deleted source]. Five months later, in an April 2026 interview with The Japan Times, he named this concept the 'Kill Web.' He described it as a network that binds South Korea, the United States, Japan, and potentially the Philippines across the land, sea, air, space, cyber, and electromagnetic domains [deleted source]. As an example, he illustrated a scenario where one country's radar tracks a target after a satellite detects signs of an attack, and another country responds [deleted source].
However, this concept is not yet an official policy document. In his written testimony submitted to the Senate Armed Services Committee on April 21 of the same year, the term 'Kill Web' does not appear at all [deleted source]. Instead, it specifies the expansion of US-ROK-Japan information sharing and investments in missile 'detect, fix, track, and destroy' capabilities [deleted source]. No document has been identified in which the Department of Defense or the Indo-Pacific Command (INDOPACOM) officially adopted this as a joint project name for the US, South Korea, Japan, and the Philippines [deleted source]. The concept runs ahead in the commander's remarks, while institutional frameworks follow behind in the form of individual programs, such as the Interoperable Multinational Network (IMN), Joint Fires Network (JFN), Project Maven (CJADC2), and the transition of US Forces Japan to a joint force headquarters [deleted source].
This asymmetry is not mere rhetoric. In the same written testimony, Commander Brunson specified that the United States would support South Korea with 'critical but more limited capabilities' [deleted source]. This is a structure where South Korea leads conventional deterrence, and US military assets function as a single node in the regional web. This sentence serves as the most concrete blueprint for the ongoing asymmetry between US-ROK and US-Japan-Australia exercises.
The Middle East Front Empties the Pacific Front
It began with Iran. As the war with Iran, triggered by Israeli and US airstrikes, dragged on longer than expected, the aircraft carrier USS George Washington, homeported in Yokosuka to guard the Western Pacific, was diverted to the Middle East on August 19 [8]. This measure was taken after the USS Abraham Lincoln, originally scheduled to return in May, was deployed consecutively for over 260 days, leading to deteriorating crew mental health and supply issues [8][10]. As a result, a gap was created in the Western Pacific, leaving no US aircraft carriers in the region for the time being [8][10].
Tensions did not stop there. In October, the Pentagon additionally deployed a third aircraft carrier strike group, centered around the USS Theodore Roosevelt, along with a Marine Expeditionary Unit to the Middle East. The force size reaches 9,000 to 10,000 personnel [1][3][17]. President Trump repeatedly hinted at the possibility of renewed airstrikes against Iran following the midterm elections on November 3 [1][7]. The structural constraint—that the US Navy's 11-carrier fleet is hard-pressed to simultaneously cover two theaters, the Middle East and the Indo-Pacific—has been laid bare in numbers through this crisis [6][8].
Around the same time, adjustments of a different nature were underway on the Korean Peninsula. On August 16, the day before the start of the Ulchi Freedom Shield (UFS) exercise, President Trump revealed on Truth Social that he had instructed Defense Secretary Hegseth to 'drastically reduce' the scale of the exercise [14][16]. The duration of the exercise was shortened from the originally planned 11 days to 5 days [14]. As justification, he cited his 'very good relationship' with Chairman Kim Jong Un, the burden of defense cost-sharing, and South Korea's lack of cooperation on the Iran issue [12][14][16]. The Ssangyong exercise was canceled altogether; however, this was due to practical constraints on US Marine Corps personnel caused by the war in Iran, which had already been communicated at the working level around June, representing a background distinct from the political announcement in August [14].
On the other side, a completely opposite trend emerged. 'Orient Shield 26,' a joint exercise among the United States, Japan, and Australia, was expanded and conducted from September 8 to 24 [2][4]. In Balikatan 2026, the IMN was operated as the primary command and control network for multinational forces for the first time [deleted source]. The Quadrilateral Defense Chiefs of Staff (QDCC) meeting among the US, Japan, Australia, and the Philippines was also launched in December 2025, and is currently working to establish a quadrilateral Common Operational Picture (COP) [deleted source]. The shrinking of one training ground and the expansion of another unfolded simultaneously on the very same calendar.
Who Is Drawing This Picture, and Why?
The blueprint for this reorganization can be found in the National Defense Strategy (NDS) released on January 23, 2026. The unclassified version specified the establishment of 'robust denial defense' along the First Island Chain [deleted source]. It also included a policy to urge and support regional allies to contribute more to collective defense [deleted source]. In an August speech in Manila, Deputy Secretary of Defense Colby stated that fully operationalizing this denial defense structure across the First Island Chain is a top priority. He explained that renaming the Indo-Pacific Command back to Pacific Command was also due to this focus [deleted source]. The same tone was repeated in the implementation status report submitted to Congress on September 22 [deleted source].
The actors implementing this strategy are multi-layered. The US Department of Defense supports the concept through its budget. In the FY27 budget, more than $2 billion was allocated to CJADC2-related items, with over $1.5 billion of that amount dedicated solely to expanding the AI-based decision-making system, Project Maven [deleted source]. In guidelines issued between March and April 2026, Deputy Secretary of Defense Feinberg defined Project Maven as the 'cornerstone' of CJADC2 and transitioned it into an official program of record [deleted source]. In his written testimony in April of the same year, INDOPACOM Commander Paparo defined information and decision superiority as a 'megatrend,' emphasizing the need to observe, orient, decide, and act (OODA) faster than adversaries through the application of space, data, and AI [deleted source].
Japan's role in this framework is distinct. The establishment of Japan's Joint Operations Command (JJOC) and the transition of US Forces Japan to a joint force headquarters, agreed upon at the US-Japan 2+2 meeting in July 2024, have been progressing in phases since March 2025 [deleted source]. In his written testimony, Commander Paparo identified joint stationing in the Southwest Islands and counterstrike capabilities as Japan's top priorities [deleted source]. Foreign Affairs pointed out that an asymmetry is emerging, where the United States delays missile shipments to Tokyo and withdraws aircraft carriers from the region, while scaling back or canceling joint exercises with South Korea and putting arms sales to Taiwan on hold [13]. Interestingly, Japan is also exposed to the same condition of the US aircraft carrier gap. The Diplomat noted that the war in Iran exposed two challenges Japan would face in the event of a Taiwan contingency [15]. This implies that the regional power vacuum is not a problem unique to South Korea.
The South Korean government is drawing a clear line in the face of this reorganization. Prior to his visit to the United States in August 2025, President Lee Jae-myung stated that the issue of strategic flexibility 'is not something we can easily agree to,' proposing instead discussions on a 'future-oriented strategic transition' [deleted source]. This indicates that South Korea still uses the balance struck in the 2006 US-ROK Joint Statement as a reference point, where South Korea 'respected' the necessity of the strategic flexibility of USFK, while the United States agreed to respect South Korea's position that it would not be embroiled in a Northeast Asian conflict against the will of its people [deleted source]. The Congressional Research Service (CRS) introduced expert assessments that the Lee Jae-myung administration is passive on this issue due to concerns over signaling a weakened deterrence against North Korea [deleted source]. The joint communique of the 57th US-ROK Security Consultative Meeting (SCM), released on November 14 of the same year, compromised on this tension. While it included phrasing that South Korea would lead the defense of the Korean Peninsula while strengthening the US conventional deterrence posture against 'all regional threats to the Alliance' [deleted source], it remained at a principled level regarding the Taiwan Strait, stating that 'maintaining peace and stability is important' [deleted source].
China is treating this reorganization as an issue of bloc-building framing rather than a military reality. The Global Times defined Orient Shield 26 as a repackaging of 'bloc politics' [2][4]. However, its response varies by region. While pouring harsh criticism toward the Philippines, it is simultaneously maintaining dialogue channels toward the Korean Peninsula, such as Foreign Minister Wang Yi's visit to South Korea [2]. German media analyzed that the war in Iran exposed the military vulnerability of the United States, and that China is closely watching this while expanding its military buildup in the Pacific [9]. It pointed out that while the United States consumes vast amounts of weaponry in the Middle East, China holds parts of the supply chain necessary to replenish those stockpiles [9].
The Issue Is Whether They See the 'Same Picture'
The prerequisite for the Kill Web that Commander Brunson cited in his interview with The Japan Times was that 'all nodes see the same picture' [deleted source]. However, this prerequisite is currently not fully met. According to reports in April 2026, the United States is withholding some North Korean nuclear-related information from South Korea [deleted source]. Trilateral information sharing among the US, South Korea, and Japan is also limited to North Korean missile warnings, and no system for sharing target data related to China has been officially confirmed [deleted source]. In other words, while the network is expanding, the flow of information remains uneven.
The second issue is when and how South Korea's C4I system will be linked to this network. In the written response of the nominee for Minister of National Defense in September 2026, consultations on linking South Korea's C4I to the IMN were officially confirmed for the first time, but they remain at the working level [deleted source]. The schedule and scope are not confirmed in public sources [deleted source].
The third issue is a matter of interpretation: whether the scaling back of exercises is a signal of abandonment or a readjustment of roles. Despite the announcement of reductions, the Freedom Edge exercise proceeded as scheduled, and the SCM explicitly stated the maintenance of the USFK posture [deleted source]. On the other hand, the shortening of UFS and the cancellation of the Ssangyong exercise suffer from procedural flaws, having been announced through the president's personal channels without going through the Ministry of National Defense's policy line [14][16]. Whether this gap will translate into a crisis of alliance credibility or settle into a new division of labor characterized by 'South Korea-led conventional deterrence' is a point that remains to be seen.
II. In-Depth Analysis
Why Did the Korean Peninsula Training Grounds Shrink While the Western Pacific Waters Emptied?
'Critical but More Limited Capabilities': A Blueprint in a Single Sentence
In USFK Commander Brunson's written testimony to the Senate on April 21, 2026, there is a striking passage. It states that as a result of alliance modernization, the United States will support South Korea with 'critical but more limited capabilities' [deleted source]. This sentence is not mere rhetoric. It contains the design principle of handing over the initiative for conventional deterrence to South Korea and repositioning US military assets as a single node in the regional network connecting South Korea, the United States, Japan, and the Philippines [deleted source]. The asymmetry—where US-ROK exercises are shortened from 11 to 5 days while US-Japan-Australia exercises expand—is merely one facet of this design principle being implemented in reality.
The root causes overlap at two levels. One is the physical limitation of resources themselves. The situation where Western Pacific aircraft carrier capabilities were emptied due to the consecutive 260-day deployment of the USS Abraham Lincoln and the diversion of the USS George Washington to the Middle East numerically demonstrates the structural constraint that the 11-carrier fleet cannot easily handle two theaters—the Middle East and the Indo-Pacific—simultaneously [6][8][10]. With the additional deployment of a third carrier strike group centered on the USS Theodore Roosevelt and a Marine force of 9,000 to 10,000 personnel to the Middle East in October, this priority appears to be locked in for the time being [1][3][17]. The other is the difference in the speed of force transition. Japan is rapidly moving toward becoming a network-type node through its acquisition of counterstrike capabilities, joint stationing in the Southwest Islands, and the transition of US Forces Japan to a joint force headquarters [deleted source]. In contrast, South Korea's defense structure is built around large-scale ground forces and a missile defense system tailored specifically to North Korea, making it difficult to immediately connect its sensors and shooters to a Kill Web structure that extends beyond national borders. When the United States reallocates resources under the same budget constraints, it is a natural choice to concentrate investments where transition costs are lower.
Priorities Revealed by the Budget Table
The structure supporting this asymmetry operates simultaneously at three levels. At the political level, the channel of announcement itself is fragmented. The scaling back of the Ulchi Freedom Shield exercise began with President Trump's personal post on Truth Social, bypassing the Department of Defense's policy line or congressional testimony [14][16][18]. Around the same time, the written testimonies of Commander Brunson and INDOPACOM Commander Paparo to the Senate delivered a message distinct from the exercise reduction, mentioning the expansion of US-ROK-Japan information sharing and the continuous assessment of South Korea's capabilities [deleted source]. This gap, where the president's personal channels and the institutional channels of the command and the Department of Defense move with different speeds and logics, keeps the adjustment of the US-ROK axis in the realm of 'signaling' rather than 'policy.'
At the economic level, budget allocation clearly points the way. In the FY27 budget, more than $2 billion was allocated to CJADC2-related projects, with over $1.5 billion of that dedicated solely to expanding Project Maven [deleted source]. In contrast, the investment schedule for platforms to fill the aircraft carrier capability gap has not been disclosed. This means that Pentagon funding is flowing toward data links and software-centric networks rather than platforms like aircraft carriers. This explains why, even as aircraft carriers are depleted in the Middle East, the center of gravity of the Indo-Pacific strategy is shifting from 'more ships' to 'a tighter net.'
At the security level, the limitations of information sharing reveal structural contradictions. The prerequisite for the Kill Web is that 'all nodes see the same picture' [deleted source]. However, trilateral sharing among the US, South Korea, and Japan is limited to North Korean missile warnings, and no system for sharing target data related to China has been officially confirmed [deleted source]. In April 2026, there were even reports that the United States was withholding some North Korean nuclear-related information from South Korea [deleted source]. The gap between the side designing the network and the reality of asymmetric information flow is a structural obstacle that must be resolved before South Korea can be fully integrated as a node.
From the Laboratory in 2019 to Seoul in 2026
Looking at the genealogy of the Kill Web concept itself makes the nature of this reorganization even clearer. This idea originated around 2019 from the concept of Mosaic Warfare pursued by DARPA and the Navy [deleted source]. The key insight at the time was that regardless of what the enemy does, friendly forces must retain options to complete the kill chain. The key was resilience—distributing functions across manned and unmanned platforms so that even if some are destroyed, the mission can be completed through alternative pathways [deleted source]. What Commander Brunson did was horizontally expand this intra-service design logic to the level of inter-state alliances [deleted source]. In the process of military-technological concepts transferring into foreign and security policy structures, South Korea has effectively become a target of role readjustment under the pretext of 'network resilience.'
As a political precedent, the 2006 US-ROK Joint Statement comes to mind. At the time, South Korea 'respected' the necessity of the strategic flexibility of USFK, while the United States agreed to respect South Korea's position that it would not be embroiled in a Northeast Asian conflict against the will of its people [deleted source]. This balance has functioned as an implicit boundary of the US-ROK alliance until now. The Kill Web concept inherently tests this boundary once again [deleted source]. It is in this context that President Lee Jae-myung, ahead of his visit to the US in August 2025, stated that strategic flexibility 'is not something we can easily agree to' and attempted to reframe the discussion with the term 'future-oriented strategic transition' [deleted source]. As noted in the expert assessments introduced in the CRS report, the South Korean government's caution is closely linked to concerns over the weakening of deterrence against North Korea [deleted source].
Further back, similarities with the Cold War-era debates on alliance burden-sharing are also noticeable. The rhetoric of the post-Vietnam War era, when the United States demanded that allies increase their own defense burdens, shares a similar tone with the current National Defense Strategy's logic of 'no single nation can bear the burden alone.' However, the differences are also clear. While past burden-sharing demands centered on conventional indicators such as troops and equipment, the current reorganization ranks allies based on a new indicator: network interoperability. The context in which South Korea's North Korea-tailored defense structure is discussed as an 'object of adjustment' also stems from this shift in indicators.
Turning to more recent cases, this can also be compared to the scaling back of exercises following the 2018 Singapore US-North Korea summit. However, while the reduction of exercises at that time was explicitly linked to diplomatic achievements between the leaders of the US and North Korea, the current phase exhibits an asymmetry where exercises are reduced first while the likelihood of resuming US-North Korea dialogue is assessed as low [16]. In that it represents a military concession without diplomatic compensation, it carries a different set of risks compared to past precedents.
Five Gauges to Watch Going Forward
The variables that will determine the direction of this reorganization can be clearly identified. First is the transition of wartime operational control (OPCON). The joint communique of the 57th SCM made it clear that the transition will be condition-based rather than time-based [deleted source]. Depending on the outcome of the Full Operational Capability (FOC) assessment of the Future Combined Forces Command in 2026, the speed of South Korea's regional role readjustment will vary.
Second is the schedule for linking South Korea's C4I to the IMN. Although the consultation was officially confirmed through the written response of the nominee for Minister of National Defense, it remains at the working level [deleted source]. If the linkage materializes, South Korea's status as a node will be elevated; if it is delayed, the designation of 'limited capabilities' is highly likely to become entrenched.
Third is the direction of the war in Iran and the timing of the aircraft carriers' return. Since the deployment of the third carrier strike group has locked in the Middle East priority for the time being, it is unlikely that the Western Pacific gap will be resolved in the short term [1][3][17]. The longer the gap persists, the greater the incentive for China to lower the threshold for its grey-zone activities in the Taiwan Strait and the South China Sea.
Fourth is whether the scope of South Korea-Japan information sharing will expand. With the current trilateral sharing limited to North Korean missile warnings, whether it expands to target information related to China will be a watershed moment in mitigating the asymmetry between the US-Japan-Australia axis and the US-ROK axis [deleted source].
Fifth is the domestic political variables of both countries. As shifts in the South Korean government's stance on strategic flexibility overlap with the Trump administration's policy adjustments toward Iran and Asia following the US midterm elections, it will be determined whether the current asymmetry remains a temporary adjustment or solidifies into a structural reorganization.
References
[1] [Hürriyet Daily News] 3rd aircraft carrier heads to Mideast as US weighs new Iran strikes
[5] [DW (Deutsche Welle)] US military buildup: What message is it sending Iran?
[7] [ANSA] Trump pronto all'escalation, una terza portaerei verso l'Iran
[11] [Al-Monitor] New US aircraft carrier heads to Middle East as Iran war stretches on
[13] [Foreign Affairs] Japan Is Giving the United States a Chance in Asia
[15] [The Diplomat] Iran War Highlights 2 Challenges for Japan in a Taiwan Contingency
[17] [Al-Monitor] Pentagon deploys thousands more Marines, another aircraft carrier to Mideast
[23] [The National (UAE)] Iran gearing up for 'major round of fighting' with US
*This text is an AI translation of an original written in Korean. Some translations or nuances may be inaccurate.
This report is an in-depth analysis planned by an EAI researcher, grounded in sophisticated AI-assisted research, and finalized by the EAI researcher.
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