The U.S.-South Korea Alliance Has Never Been This Close, or This Fragile

It is the best of times and the worst of times for the future of the U.S.-South Korea alliance. South Korean perceptions of economic coercion in the context of U.S. efforts to rebalance global trade, doubts about the credibility of nuclear deterrence in the face of multiple proliferation threats, and unease regarding the U.S. prioritization of China at the seeming expense of North Korea have been eating away at South Korea’s confidence in the United States as its security guarantor. 

“Alliance modernization,” much discussed between the two allies this decade, lands to some as a euphemism for alliance degradation, with the transition in operational control arrangements, the Lee Jae Myung administration’s emphasis on self-reliance, and not-so-subtle nudges from the Pentagon for South Korea to take the lead in deterring North Korea as factors that some may perceive as weakening alliance capabilities and commitments. 

Yet, under the moniker of “pragmatic diplomacy” to address a worsening regional security environment, the Lee administration has pledged unprecedented flows of South Korean investment into the United States, pitched South Korea as a valuable partner and technology provider for shipbuilding cooperation, strengthened industrial cooperation, sought defense-industrial integration, and supported alliance modernization as a “model ally” by taking greater operational responsibilities and contributing valuable capabilities to allied deterrence against China and North Korea.

With investment pledges of up to USD 150 billion during the Joe Biden administration and an additional USD 350 billion under a new technology prosperity deal with the Donald Trump administration, South Korean companies have emerged as significant investors in the grand project of American reindustrialization. Shared alliance interests and values undergird South Korean investments through a patchwork of battery, automobile, and semiconductor facilities that now dot portions of the American South, Southwest, and Midwest. 

The emergence of South Korea as a technology provider is deepening a partnership powered by chips, batteries, and critical technologies. The flow of economic investment in the United States balances the longstanding U.S. commitment to South Korean security, addresses structural inequalities, and places the relationship on a more sustainable footing—but only if South Korean companies can integrate seamlessly into the U.S. business environment.

In the spirit of the alliance, South Korea launched one of the shrewder responses last year to the Trump administration’s use of tariffs to rebalance global trade and induce U.S. reindustrialization with its proposal to “Make American Shipbuilding Great Again” (MASGA). Under this initiative, South Korea has pledged to support maintenance, repair, and operations (MRO) to repair U.S. ships in Korean ports, invest in technology, workforce training, and the establishment of an ecosystem for the revitalization of U.S. shipbuilding through investment in the Hanwha Philly Shipyard, and cooperate in the construction of nuclear-powered submarines.

Cooperation between the United States and South Korea in shipbuilding should pave the way for partnerships in other areas of defense-industrial production, especially as South Korea’s defense-industrial ties expand with other U.S. partners in Eastern Europe and the Middle East. South Korea’s capacity to meet growing demand for missile defense and other products should jumpstart new forms of near-term cooperation while also signaling a durable strategic commitment to the U.S.-South Korea alliance. Such cooperation may extend to the energy sector as South Korea is well positioned to work with the United States to build safe nuclear power plants on time and on budget to meet AI-driven energy demand. 

Finally, the Trump and Lee administrations are refashioning the security relationship in response to a growing dual nuclear threat from China and North Korea.  Alliance modernization requires continued adaptation of nuclear cooperation arrangements, investment in defense capabilities, and the adaptation of strategies to new domains such as cyber and space. South Korea has increased its defense contributions and is discussing cooperation to address both peninsular and regional security threats in Northeast Asia, thereby enhancing South Korea’s own capabilities and contributions to the alliance. 

These adaptations underway in response to rising superpower rivalry are inevitable and necessary. While the organizational root structure of the relationship has never been more coordinated, integrated, and dynamic, the Trump and Lee administrations are taking steps to ensure that the alliance structure remains healthy and durable.

Scott Snyder is President and CEO of the Korea Economic Institute of America (KEI) and author of The U.S.-South Korea Alliance: Why It May Fail and Why It Must Not. The views expressed here are the author’s alone.

This material is distributed by KEI on behalf of the Korea Institute for International Economic Policy. Additional information is available at the Department of Justice, Washington, DC.