The Peninsula

Under Trump the US-ROK Alliance Will Increasingly Be About China

Uncertainty prevails when it comes to the incoming Donald Trump administration and the US-ROK alliance. Observers are feverishly speculating on a range of potential policy trajectories from universal and across-the-board 10-20 percent tariffs, obstructed implementation of the Inflation Reduction Act (IRA), and less flexible US export controls to increased cost- and burden-sharing demands related to the stationing of US forces on the Korean Peninsula and fears that Trump could strike a deal with Kim Jong Un that sidelines Seoul and results in de facto acceptance of North Korea as a nuclear-weapon state. Time will tell if—and to what degree—President-elect Trump will pursue any of these courses of action.

What is certain, however, is that US defense and military officials will increasingly view the alliance through the lens of US-China competition. This trend preceded yet picked up speed under the first Trump administration, continued under President Joe Biden in a more consensual but no less marked manner, and will accelerate again under a second Trump administration. It is also a trend the Yoon Suk-yeol administration helped foster by jettisoning its progressive predecessor’s policy of strategic ambiguity in favor of strategic clarity and establishing its own Indo-Pacific Strategy amidst a growing US-China rivalry.

Nonetheless, many in South Korea appear unready or unwilling to fully grapple with the stark implications implicit in such a trend. Instead, voices in Seoul have begun to talk about developing autonomy in the face of Trump’s return. Of course, if Trump were to remove or withdraw US forces, greater autonomy would become essential. However, so long as US forces remain stationed on the Korean Peninsula and Seoul depends on Washington for its ultimate national security—codified in a mutual defense treaty that applies to the entire “Pacific Area”—Seoul’s autonomy will remain inherently limited.

Moving forward, US defense and military officials will continue to push for tighter operational and strategic linkages between the Korean Peninsula—and the alliance itself—and the broader Indo-Pacific theater. This is particularly apparent in the Regional Sustainment Framework (RSF) of the US Department of Defense (DOD) and its effort to establish a distributed maintenance, repair, and overhaul (MRO) network to support the Joint and Combined Force. Notably, Trump—while not mentioning the RSF specifically—highlighted elements of it during his first phone call with President Yoon, when he reportedly said the United States seeks to work with South Korea in the shipbuilding industry, specifically in naval shipbuilding, exports, repairs, and maintenance.

Regional sustainment—the provision of logistics and personnel services to maintain and prolong operations through mission accomplishment and force redeployment—relates to the brass tacks of interconnectivity, with clear implications for South Korea’s own contributions to and embeddedness within a US-led regional architecture, including in a potential crisis or conflict between Washington and Beijing. Even though South Korea’s main national security priority will remain centered on deterring and defending against North Korea, that focus can no longer be siloed off from the region or Seoul’s own responsibilities therein. Such a reality will soon become more real, offering both opportunities and stark challenges for the alliance.

Fitfully Interconnecting the Indo-Pacific

From the earliest post-Cold War years, US policymakers identified the Indo-Pacific (then called the Asia-Pacific) as a region whose global importance would continue to grow. President Obama’s pivot or rebalance to Asia—with antecedents under the George W. Bush administration—represented a belated acknowledgment of the region’s significance to US national interests and a commitment to shift greater attention and resources thereto.

While the terminology and points of emphasis evolved across administrations, the underlying aim for US military and defense officials has been to strengthen US connections to, between, and among existing allies and partners. Maintaining US strategic preponderance (or strategic primacy) while shaping and navigating China’s rise drove the effort. So, too, did a growing concern that the US force posture in the region was not fit for the purposes of competition, not to mention a potential conflict with, China.

Whether called a networked security architecture or latticework, a consistent goal remained: a strengthened, more distributed, resilient, flexible, interconnected, and politically sustainable US force posture in the region, which increasingly leaned upon allies’ capabilities and national capacities. Nonetheless, a combination of budgetary constraints, constant conflict in the Middle East, inter-service rivalries and conflicting resourcing priorities, and longstanding inertia surrounding US forward deployments in the Indo-Pacific, including allies’ concerns about being drawn too far into US-China competition, have all complicated achieving the goal of a more distributed and flexible posture.

All the while, concerns have grown about a potential conflict over Taiwan, with open-source war-gaming showing the enormous costs of such a conflict and that, to one degree or another, allied involvement is necessary. However, such games often “assume away any logistics and sustainment problems, because if you play them for real, it screws up the game.” In this context, greater effort is being put into regional sustainment and improving operational readiness and effectiveness in a contested logistics environment within the Indo-Pacific.

The Shadow of Ukraine in the Indo-Pacific

The war in Ukraine amplified awareness about a potential conflict in the Indo-Pacific and the stark sustainment challenges therein. Supporting and supplying Ukraine has been complicated not just by political obstacles and fears of escalation but also by limited stockpiles, the need to overhaul defense industrial base capacities required to generate and sustain critical supplies, and more efficient logistical arrangements to move supplies where needed. Nevertheless, as challenging as these issues have been in Ukraine, they pale in comparison to a possible conflict over Taiwan between the United States and China.

Western Europe serves as a massive beachhead of rear area support for Kyiv, consisting of a largely (mostly) uncontested logistics environment within which the United States and its NATO partners have avoided direct kinetic attacks. In a conflict over Taiwan, it would be the complete opposite. Washington and its allies and partners would face the tyranny of a massive maritime geography, long and highly contested lines of communication, and constant multi-domain threats and kinetic and/or cyberattacks across the entire supply chain.  ​

Informed by the war in Ukraine and aligning with DOD’s reference to the Indo-Pacific as the “priority theater” and a possible conflict over Taiwan as the “pacing scenario,” the 2022 National Defense Strategy’s call for integrated deterrence to address China as the “pacing challenge,” and the inaugural National Defense Industrial Strategy (NDIS) released in January 2024, the DOD released the aforementioned RSF in May 2024. The RSF aims to enhance sustainment capabilities in-theater by developing a distributed network of MRO facilities closer to the point of need and collaborating with allies and partners. South Korea has leaned into these efforts both before and after the RSF was released.

One month after the DOD released the RSF, US and South Korean defense officials held the 24th Korea-U.S. Integrated Defense Dialogue (KIDD) in Washington on April 11. In addition to highlighting that cooperation in advanced technologies helps enhance both countries’ defense industrial bases, the KIDD’s joint press statement noted their in-depth discussions on the RSF to facilitate logistics in a contested environment, cooperation to distribute MRO in the Indo-Pacific, and South Korea’s efforts to collaborate on MRO initiatives “in accordance with the direction of enhancing the Alliance’s posture and capabilities.” It was the first time that “MRO” was included in a formal bilateral alliance statement released by senior US and South Korean defense officials. By the 56th Security Consultative Meeting (SCM) on October 26, significant progress had been made.

US and South Korean defense authorities had included mention of sustainment and/or logistics in the Joint Communique going back to the 50th SCM in 2018, yet always in small, standalone passages, with a narrow bilateral and peninsular emphasis. However, last month’s communique folded such language into a longer and more regionally framed passage. The passage noted progress under the RSF and welcomed South Korea’s participation in an MRO pilot project on Air Force maintenance, which could portend future bilateral co-sustainment opportunities and “expand defense industrial collaboration with like-minded partners in the region in light of the ROK’s key role in the Partnership for Indo-Pacific Industrial Resilience (PIPIR) contact group.”

Moreover, the communique “noted with satisfaction the recent U.S. Navy contract with ROK shipyards to conduct MRO services for U.S. vessels, and underscored the potential to expand such work to improve the resilience of the Alliance’s posture in the Indo-Pacific Region.” The latter was a reference to Hanwha Ocean’s Geoje shipyard securing a contract in August to overhaul a 40,000-ton US naval ship, becoming the first South Korean shipyard to secure a ship MRO contract from the US Navy. Similarly, HD Hyundai Heavy Industries secured the right to bid for such MRO contracts in July.

Shared Goals…to a Point

The three primary goals of the DOD’s RSF present opportunities for South Korea and the alliance, yet also serious challenges. The third listed goal—to “Strengthen Regional Partnerships”—is the lowest-hanging fruit. It is already being actualized in the Air Force and Navy MRO projects mentioned above, along with a range of similar projects Washington is pursuing with other allies and partners in the region. Seoul’s eager embrace of such a goal bolsters Korean defense firms’ bottom lines, offers avenues to greater defense exports, and, if Trump and Yoon’s first phone call is any indication, could enhance the reality and perception of Seoul’s increased burden-sharing. The latter might reduce Trump’s desire to reopen Special Measures Agreement (SMA) talks and demand Seoul cover the entire cost (plus more) of stationing US forces in Korea.

The RSF’s second listed goal, to “Enhance Military Readiness,” also offers valuable opportunities yet reveals points of friction in the alliance. On the one hand, to enhance readiness, the DOD “will collaborate with allies and partners to understand their national defense and security priorities.” This is critical for a successful US strategy and for Seoul as it navigates advancing North Korean capabilities and aggressive or coercive intent on the peninsula amidst a more complex strategic environment. On the other hand, the DOD aims to understand allied priorities and “incorporate those perspectives to build regionally focused product support/sustainment strategies” and “increase the Joint and allied force’s ability to rapidly regenerate readiness, respond to persistent threats, and deter regional aggression.” Put simply, the higher objective embodied in the second goal is to fold allies like South Korea into a broader US regional project beyond the Korean Peninsula, undoubtedly centered on China.

Incoming Four-Star General and Commander of US Forces in Korea, Lieutenant General Xavier T. Brunson, has indicated as much. Although he reiterated the primary purpose of US forces and the US-ROK alliance was deterrence and defense on the Korean Peninsula, he observed that the mutual defense treaty “does not name a specific adversary”; US forces in Korea serve “as a deterrence to our adversaries,” creating “multiple dilemmas to DPRK, PRC, and RUS”; and he will “continue to advocate for inclusion” of such forces and capabilities into Indo-Pacific exercises, wargames, contingencies, and operational plans supporting US interests and objectives in the region. This requires talking through the operational and strategic implications of such a shift with South Korean counterparts. However, such discussions are at an incipient stage, at best.

The need to move such discussions forward is even more apparent given the RSF’s first goal: to “Prevail in a Contested Logistics Environment” by establishing “a distributed MRO ecosystem that remains viable in peacetime and meets surge requirements during crises and conflicts.” Such an ecosystem, if credibly and effectively established, may enhance deterrence and reduce the chances of a regional contingency or conflict by demonstrating to Beijing (and others) that Washington and its allies are prepared and possess an array of MRO nodes bolstering their resilience if one were to occur. China would face multiple dilemmas insofar as targeting such infrastructure across various countries would present significant risks, the cost of which could well exceed the benefits of initiating or continuing a conflict. Yet, the necessary steps to establish such an ecosystem and deter conflict also foster expectations that US allies would indeed be committed to supporting the United States if one were to arise.

Again, this is not a new trend. Yet, it has picked up speed in recent years as US defense and military officials have grappled with the fact that in the event of a conflict with China over Taiwan, there would be the potential for both vertical and horizontal escalation and simultaneous conflict (particularly in Korea) and that they would need to utilize the entire US force posture and defense infrastructure in the region, including as much unencumbered access as possible on allied and partner territory and those same allies and partners’ national capacities. No matter how Seoul (or Tokyo, Canberra, and Manila) has perceived its bilateral treaty commitment with Washington in the past, ineluctable changes are underway.

Concluding Thoughts

Although Washington and Seoul are in sync in building regional partnerships under the RSF and understand it is driven by intensifying US-China strategic competition, they differ in their ultimate aims. Washington aims to build such partnerships to prevail, from peaceful competition, to low-intensity competition and coercion short of war, to armed conflict. Seoul aims to bolster its status as an ally and strengthen the US-ROK alliance, to navigate intensifying US-China competition and avoid conflict. Yoon’s recent remarks that Seoul’s relations with Washington and Beijing are not about choosing sides—a refrain also voiced by his progressive predecessor’s administration that Yoon has strenuously critiqued—show the depth of this sentiment within South Korea.

Under the second Trump administration, defense and military officials will continue the existing trend of increasingly subsuming the US-ROK alliance through the lens of US-China competition in the Indo-Pacific. However, what remains unclear is how Trump himself will guide the process. If he adopts a hawkish and primacy-based mindset toward China while simultaneously degrading alliances by making outlandish cost-sharing demands and reducing or withdrawing US forces from the region, he will increase the chances of a conflict while undermining the United States’ ability to effectively respond to one. America first may quickly become America alone.

 

Clint Work is a Fellow and Director of Academic Affairs at the Korea Economic Institute of America. The views expressed here are the author’s alone.

Official White House Photo by Adam Schultz from White House flickr photostream.

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