[Global NK Commentary] The Future of U.S. Maritime Hegemony and South Korea's Strategy: The Role of the U.S. Congress in ROK-U.S. Shipbuilding Cooperation and North Korea Policy

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ROK-U.S. Shipbuilding Cooperation and MASGA: The First Step Towards a Comprehensive ROK-U.S. Alliance

The term MASGA (Make American Shipbuilding Great Again) was coined by the South Korean delegation after considerable deliberation during negotiations to lower tariffs for the second Trump administration. Ideas and proposals for ROK-U.S. shipbuilding cooperation had actually been raised long before the tariff negotiations. In reality, the tangible outcomes of ROK-U.S. shipbuilding cooperation have fallen short of expectations, despite the frequency with which it has been reported in the media. For instance, as early as February of last year, U.S. Secretary of the Navy Carlos Del Toro visited HD Hyundai Heavy Industries' Ulsan shipyard and Hanwha Ocean's Geoje shipyard, inspecting their production facilities and warship construction capabilities. Although the domestic shipbuilding industry has declined, ROK-U.S. shipbuilding cooperation is essential for the United States, which is facing an urgent need to compete with China in naval power. For South Korea, which possesses world-class shipbuilding capabilities and for whom cooperation with the United States is absolutely crucial on numerous diplomatic issues, including the North Korean nuclear issue and relations with China, ROK-U.S. shipbuilding cooperation can be an important first step towards a comprehensive ROK-U.S. alliance where both sides can willingly give and take. However, to achieve substantial progress in ROK-U.S. shipbuilding cooperation going forward, South Korea needs to clearly recognize the domestic political and legal obstacles in the United States and make proactive efforts to overcome them.

Naval Power Enhancement and Shipbuilding-Related Legislation, and Legal Constraints on ROK-U.S. Shipbuilding Cooperation

Recently, a somewhat encouraging bipartisan bill was introduced in the U.S. Congress. On August 1, Representative Ed Case (Democrat, Hawaii) and Representative James Moylan (Republican, Guam) jointly introduced the Merchant Marine Allies Partnership Act. This bill proposes a 50% tariff exemption on imports for U.S. vessels undergoing modifications at shipyards in allied nations such as South Korea and Japan, and permits allied-built vessels to engage in coastal transport within the U.S. The Jones Act of 1920 stipulates that all vessels navigating U.S. coastlines must be built, owned, and operated by Americans; the Merchant Marine Allies Partnership Act seeks to exempt allies from these regulations for shipbuilding cooperation. This bill is currently pending before the House Committee on Transportation and Infrastructure.

In addition to the Jones Act, the Byrnes-Tollesfson Act poses a legal constraint on shipbuilding cooperation with allies. The Byrnes-Tollesfson amendment prohibits the U.S. Navy from directly contracting with foreign shipyards for the construction of naval vessels. It also prohibits contracts through subcontractors or sub-subcontractors. While the President's waiver authority is provided as an exception, the circumstances under which the President could exercise this waiver are practically very limited, except in special situations like wartime. The Byrnes-Tollesfson Act also contains separate provisions prohibiting the maintenance, repair, and overhaul (MRO) of vessels overseas. According to this provision, naval vessels homeported in the U.S. or Guam cannot receive maintenance, repair, or overhaul services at shipyards outside the U.S. or Guam. However, exceptions are made for Littoral Combat Ships (LCS), repairs during navigation, and repairs for damage caused by hostile actions or intervention.

As of 2024 data, out of 296 U.S. naval vessels, only 40 are homeported at bases outside the U.S., and there are only 22 Littoral Combat Ships in total. Therefore, unless the Byrnes-Tollesfson Act is amended, ROK-U.S. shipbuilding cooperation is unlikely to materialize, particularly for South Korea, which does not have homeports for U.S. naval vessels like the U.S. naval bases in Yokosuka and Sasebo, Japan. Japan is responsible for the maintenance, repair, and overhaul (MRO) of U.S. naval vessels homeported in Yokosuka and Sasebo. The two MRO projects undertaken by Hanwha Ocean in November 2024 were legally possible because they were commissioned by the U.S. Seventh Fleet, which does not have a homeport in the U.S. or Guam. On August 6-7, Kang Hwan-seok, Deputy Administrator of the Defense Acquisition Program Administration (DAPA), visited Washington and met with Assistant Secretary of the Navy for Research, Development, and Acquisition, Jason Porter, reportedly discussing and reaching a consensus on the need to ease regulations in the Byrnes-Tollesfson Act, which restricts the construction of U.S. naval vessels to U.S. shipyards. According to the report, Deputy Administrator Kang suggested various cooperation methods, such as South Korean shipbuilders constructing vessels or producing and supplying block modules for final assembly at U.S. shipyards, considering the current legal framework.

It is noteworthy that while such bills receive significant media coverage during their introduction phase, introduction is merely the initial stage of legislation. If a bill is not referred to a committee, or if it is referred but remains pending or fails to pass votes in both the House and Senate, it will not lead to any substantial change. This fact highlights the significant role of Congress in the practical advancement of U.S. naval power enhancement and ROK-U.S. shipbuilding cooperation. In fact, a bill to amend the Byrnes-Tollesfson Act to allow allied nations to build U.S. naval vessels (Ensuring Naval Readiness Act: ENA Act) was introduced in June 2024. However, no follow-up action was taken, and it was reintroduced in February 2025 and is currently pending before the Senate Committee on Armed Services. The Shipbuilding and Harbor Infrastructure for Prosperity and Security for America Act (the SHIPS Act), a bill linked to the Trump administration's April executive order, has also been referred to the relevant committees in the Senate and House, but no hearing dates have been scheduled. Similarly, the Open America’s Waters Act, introduced last June to allow foreign vessels to transport goods along U.S. coastlines, is in the same situation. Among the four bills mentioned above, the Merchant Marine Allies Partnership Act, introduced most recently, appears to be the most advanced, but even this bill may be held up in committee or may not pass a vote in the House or Senate, depending on circumstances.

Weakening Momentum for the Second Trump Administration's Maritime Action Plan

Historically, maritime hegemons have sought to enhance their naval power during periods of strategic maritime power shifts by maximizing domestic resource extraction capabilities or by redeploying naval assets from other theaters to the theater experiencing the power shift. The current quantitative maritime power shift between the U.S. and China is a prime example. The Trump administration's second term executive order in April, titled "Restoring America’s Maritime Dominance," and its accompanying Maritime Action Plan, represent a typical effort of the former. However, with the deadline for submitting this Maritime Action Plan—which involves the mobilization of the State Department, Department of Defense, Department of Commerce, Department of Labor, Department of Transportation, U.S. Trade Representative, and Department of Homeland Security—approaching within two months, the situation within the Trump administration appears challenging.

This is because key personnel responsible for the Maritime Action Plan at the White House and the maritime office have recently departed the administration. Ian Bennitt, who served as Senior Advisor for Maritime and Industrial Capacity at the White House National Security Council, left the Trump administration at the end of July. His departure, following that of Brian McCormack, Chief of Staff of the National Security Council, adds to the personnel losses after five of the seven staff members of the maritime office resigned in July. This exodus of personnel in July raises the possibility that the momentum for implementing the April executive order and the Maritime Action Plan is weakening at the administrative level. While it is prudent to avoid hasty judgments until the specific contours of the Maritime Action Plan are revealed in two months, it can be said that the administration's drive to implement the executive order has somewhat weakened compared to April.

Meanwhile, the legislative branch, along with the executive branch, plays a crucial role in enhancing a maritime hegemon's resource extraction capabilities. In the late 19th century, when the alliances between France and Russia challenged Britain's naval supremacy in the Mediterranean, the British Parliament passed additional legislation (Naval Works Act of 1895, Naval Works Bill of 1896) for the construction of warships and improvement of coastal facilities outside the naval budget, alongside the Spencer Program of 1893. In the 1930s, the U.S. Congress also passed successive warship construction bills from 1934 onwards to counter the maritime power shift initiated by Japan. Moving forward, the extent to which the Trump administration can regain momentum for its Maritime Action Plan, and whether the current U.S. Congress will actively support naval and shipbuilding-related legislation, will influence the potential for U.S. naval power enhancement. In particular, for South Korea to participate in shipbuilding cooperation, such as warship construction or MRO, legal restrictions on the shipbuilding sectors of allied nations must be removed through Congress.

Simultaneous Engagement with the Executive and Legislative Branches and Approaches to North Korea

For the Trump administration's Maritime Action Plan to succeed, bills related to naval power enhancement, shipbuilding investment, and shipbuilding and MRO cooperation with allies, introduced in Congress, must simultaneously achieve substantial progress. Only then will the U.S. be able to adequately respond to the quantitative maritime power shift caused by China in the long term. However, given the current situation, it is uncertain whether the progress in warship construction and shipbuilding revitalization intended by the executive and legislative branches will materialize, and if so, when. While the necessity of U.S. naval power enhancement is shared to some extent by both the executive and legislative branches, other domestic political factors may act as obstacles to amending existing laws and enacting new legislation. For example, the metalworkers division of the American Federation of Labor and Congress of Industrial Organizations (AFL-CIO), the largest labor union in the U.S., has opposed bills allowing the use of allied shipyards since the Biden administration. If the steelworkers' union, based on its organizational strength, opposes and lobbies on the grounds that it would harm their job security, politicians will be unable to ignore such pressure.

Stakeholders in the U.S. shipbuilding industry view the outsourcing of U.S. combatant warship construction as a serious threat to the American shipbuilding sector. They oppose amendments to current laws and new legislation while demanding greater investment in U.S. shipbuilding infrastructure. This opposition is not unrelated to the fact that the U.S. shipbuilding industry is heavily reliant on the warship market. In 2020, less than 3% of the total vessels delivered by the U.S. shipbuilding industry were supplied to U.S. government agencies, but 14 out of 15 large deep-sea vessels were delivered to the U.S. Navy and Coast Guard. The U.S. shipbuilding industry still maintains strong protectionist sentiments regarding warship-related matters. Furthermore, if national security concerns are added, such as the potential for leakage of information or technology related to weapon systems when combatant warships are built at foreign shipyards, opposition to building warships at foreign shipyards could intensify. Some also express concern that the fact that South Korean shipyard workers have been employed at Chinese shipyards in recent years exacerbates these concerns. The repeated failures to repeal the Jones Act over the past 100 years attest to the powerful influence of lobbying by the U.S. shipbuilding industry and labor unions.

Considering these domestic political circumstances in the U.S., for South Korea to properly realize the MASGA project, which it proposed as leverage during tariff negotiations, it needs to engage in active lobbying of the U.S. Congress in addition to close consultation with the U.S. executive branch. The consultation between DAPA and the U.S. Department of the Navy on August 6-7 mentioned earlier can be considered a consultation between the ROK and U.S. executive branches. While cooperation between the ROK and U.S. executive branches may also be affected by the recent delays in tariff negotiations, the executive order and Maritime Action Plan from the Trump administration have already been announced. As time passes and concerns about the naval power gap with China and the threat perception intensify, the demand for shipbuilding modernization and rapid warship construction will gain traction. From South Korea's perspective, to prevent this political momentum from being lost in the U.S., it is necessary to engage not only with the executive branch but also with Congress, businesses, and civil society. By forming a network for lobbying the U.S. Congress collectively through the South Korean National Assembly, businesses, and civil society, and by continuously making engagement efforts towards not only the U.S. executive branch but also Congress, the political foundation for ROK-U.S. shipbuilding cooperation can be laid, and obstacles at the level of U.S. domestic law can be overcome.

As mentioned, South Korea's multifaceted engagement efforts with the U.S. Congress are primarily necessary for ROK-U.S. shipbuilding cooperation related to U.S. naval power enhancement. Furthermore, South Korea's engagement with Congress is also needed to narrow the differences in opinions between South Korea and the U.S. on issues such as non-proliferation, peace regime, and the size and role of U.S. Forces Korea, which are intertwined with North Korea, and to promote stability in the Asia-Pacific region surrounding the Korean Peninsula. Although media reports have suggested that the second Trump administration might reduce U.S. Forces Korea, the U.S. Senate Committee on Armed Services passed the National Defense Authorization Act for Fiscal Year 2026 on July 11, including a provision prohibiting the reduction of U.S. Forces Korea or the transfer of wartime operational control to the Combined Forces Command unless the Secretary of Defense certifies to Congress that such actions are in the U.S. national interest. Although this is an annual law that changes with the evolving security environment, it should be noted that the U.S. Congress also has influence over the size of U.S. Forces Korea. Therefore, efforts should be made to ensure that the U.S. Congress approaches the issue of the size and role of U.S. Forces Korea based on an understanding of South Korea's long-term North Korea policy. Furthermore, through this, the long-term goals of South Korea and the United States regarding North Korea should be adjusted as North Korea's nuclear capabilities advance. Establishing a robust consultation framework with the U.S. Congress, which holds a firmer stance on denuclearization, will have the effect of ensuring that ROK-U.S. cooperation is built upon the shared long-term vision of denuclearization and the establishment of a peace regime. The simultaneous engagement policy towards the U.S. executive and legislative branches may begin with U.S. naval power enhancement and ROK-U.S. shipbuilding cooperation, but active engagement with the U.S. Congress can also play a positive role in sharing the long-term vision of denuclearization and a peace regime between South Korea and the United States in North Korea policy. ■

■ In-Hwan Oh_Senior Fellow at EAI; Lecturer at Seoul National University.

■ Edited by: In-Hwan Oh_Senior Fellow at EAI; Jonghyuk Jung_Research Fellow at the Korea National Diplomatic Academy

Contact: 02 2277 1683 (ext. 202) | ihoh@eai.or.kr