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I. Trump 2.0's Maritime Action Plan (MAP)

 

On April 9, 2025, the Trump administration issued an executive order titled "Restoring America's Maritime Dominance," which articulated a comprehensive agenda to revitalize American shipbuilding capacity and maritime workforce. The directive enumerated an array of policy instruments aimed at restructuring shipbuilding supply chains and compensating for the erosion of U.S. maritime industrial bases. Its core objectives include securing durable federal funding for shipbuilding, enhancing the international competitiveness of U.S.-manufactured or U.S.-flagged merchant vessels, expanding the Maritime Industrial Base, and strengthening the recruitment, training, and retention of the relevant workforce.

 

The Assistant to the President for National Security Affairs (APNSA), in consultation with the Secretaries of State, Defense, Commerce, Labor, and Transportation, the United States Trade Representative, and the Secretary of Homeland Security, is tasked with submitting a Maritime Action Plan (MAP) to the President within seven months. This plan is to incorporate policy measures that not only stimulate investment in critical maritime supply chains but also scrutinize China's potentially unfair practices in the global shipbuilding industry, which potentially includes the imposition of tariffs.

 

The executive order also mandates the establishment of Maritime Prosperity Zones to attract domestic and allied investment into the U.S. maritime sector, alongside the creation of a Maritime Security Trust Fund to ensure the MAP's sustained implementation. Particularly notable is the MAP's emphasis on overcoming longstanding inefficiencies in naval shipbuilding and addressing the aging and shrinking workforce through enhanced training and systemic reforms. The plan further advocates increasing the number of U.S.-flagged commercial vessels, which could be requisitioned for military use during contingencies. In parallel, the Secretary of Defense must conduct a comprehensive review of an inactive reserve fleet within three months and submit guidelines for its funding, retention, support, and mobilization.

 

II. U.S.-China Naval Power Transition in the 21st Century

 

The MAP demonstrates the United States' recognition of its relative hegemonic decline amid an ongoing structural shift in the international system. Although China's GDP stagnated around $17 trillion between 2021 and 2024, and the U.S. economy expanded from $24 trillion to $29 trillion in the same period, the underlying dynamics of the U.S.-China power transition remain intact. Both Trump and Biden administrations, despite ideological differences, pursued variants of supply chain reconfiguration and de-risking strategies, signaling bipartisan concern over China's rise. The Biden administration notably rejected the WTO's ruling that Trump-era tariffs on steel and aluminum violated trade rules. On May 31, 2025, President Trump announced a further increase in these tariffs, from 25 to 50 percent.

 

Despite the divergences in grand strategy between the Biden administration and the first and second Trump administrations, a notable continuity exists in their respective China policies. This consistency is closely tied to the ongoing structural transformation represented by the U.S.-China power transition. As emphasized in various theories of international relations—such as hegemonic stability theory (Charles Kindleberger, Robert Gilpin), power transition theory (A.F.K. Organski), and long-cycle theory (George Modelski)—the trajectory of power transitions can be traced through numerous indicators, including military strength, economic capacity, financial influence, industrial productivity, technological advancement, knowledge production, and norm-diffusion. Among these, the most salient contemporary transition between the United States and China is occurring in the maritime domain.

 

During the 17th and 18th centuries, naval power transitions were relatively frequent among Portugal, Spain, the Netherlands, Britain, and France. In contrast, the 19th and 20th centuries witnessed intensified naval competition among Britain, France, Germany, the United States, and Japan, but very few instances where one power overtook another. The most notable examples are Britain and France in the early 1860s, and Britain and the United States during the interwar period, particularly in 1919 as well as the 1930s.

 

Given Britain's strategic decision in 1904, following the Venezuelan Crisis of 1895 and the rising threat posed by Germany in continental Europe, to accommodate the ascendant United States within the international system, the Anglo-French shift of the early 1860s may well be the only conventional example of a naval power transition across both the 19th and 20th centuries. Although the Anglo-German naval race of the early twentieth century is often cited as a classic case, Germany never surpassed British naval power. Similarly, although Japan sharply narrowed its naval gap with the United States by 1941 through a concentrated mobilization of domestic resources, the Roosevelt administration and Congress countered this effort by enacting a series of legislative measures: the Vinson-Trammell Act of 1934, the Second Vinson Act of 1938, and the Two-Ocean Navy Act of 1940. These acts effectively forestalled Japan's naval overtake in the Asia-Pacific theater.

 

In response to China's full-scale naval modernization, which began in earnest around 2012, the U.S. Congress has, since 2015, consistently authorized more funding for warship production than requested by the President. The executive branch itself has also gradually increased its annual shipbuilding budget from approximately $15 billion in 2015 to $30 billion by 2025. The problem, however, lies in the comparative productivity of the shipbuilding sectors of America and China. China, having designated naval modernization as a strategic priority and co-leading the global shipbuilding market alongside South Korea, has been able to produce far more warships within the same timeframe.

 

According to a March 2025 analysis by the Center for Strategic and International Studies (CSIS), China and South Korea account for 53.3 percent and 29.1 percent of global shipbuilding output, respectively, while the United States holds a mere 0.1 percent share. In terms of combat ship count, China's quantitative overtaking of the United States occurred between 2015 and 2020. The U.S. Department of Defense's 2024 report on Chinese Military Power states that the Chinese Navy currently possesses 370 warships, making it the largest in the world by total hulls. This figure is expected to rise to 395 by 2025 and 435 by 2030. By comparison, the U.S. Navy operated approximately 296 warships as of December 1, 2024, and according to the 2025 Navy's proposal, it is projected to maintain 294 combat ships by the end of fiscal year 2030.

 

III. Asymmetries in Shipbuilding Capacity and the Future of Naval power

 

In the early 2000s, international relations scholars debated why balancing behavior failed to materialize against the United States despite its unparalleled military primacy. According to balance of power theory, states tend to form counter-coalitions against a hegemon that concentrates overwhelming military capabilities. Yet in the post-Cold War era, such balancing against the United States has been conspicuously absent. One line of explanation argues that the United States, as the leading sea power, does not pose the kind of direct territorial threat associated with continental powers, and therefore does not provoke balancing in the conventional sense. This perspective, which situates threat perception and security competition within a geographic and geopolitical framework, is undoubtedly insightful. However, it also contains a critical blind spot. In the 21st century, very few states possess the economic, fiscal, and industrial capacity, most especially in shipbuilding, to engage in a full-scale naval competition with a leading sea power.

 

The declining frequency of naval power transitions in the 19th and 20th centuries, compared to the 17th and 18th, may well underscore the importance of economic strength and shipbuilding capability. France and Russia both attempted naval competition with Britain during the nineteenth century, but aside from France in the early 1860s, no naval power transition occurred. In the twentieth century, Germany, Japan, Russia, and the Soviet Union each challenged British or American naval dominance, yet none succeeded in surpassing the Anglo-American maritime powers. By contrast, 21st century China, despite certain qualitative disadvantages, has already acquired the economic, fiscal, and industrial foundation necessary to challenge the United States in a sustained naval competition. In this context, whether other states are willing to form a balancing coalition against the United States becomes largely irrelevant. The very process of China's naval modernization already constitutes a form of structural balancing.

 

Admittedly, the number of warships cannot serve as an absolute or exclusive metric for evaluating naval power. In terms of fleet composition, the U.S. Navy maintains a larger number of capital ships such as cruisers and destroyers, while the Chinese Navy possesses more smaller surface combatants such as frigates and corvettes. The United States operates eleven aircraft carriers, whereas China currently operates three and is constructing a fourth. When measured by total displacement, the Chinese Navy accounts for approximately 1,854,000 tons, which is less than half the U.S. Navy's 4,000,000 tons. In the submarine domain, all U.S. submarines are nuclear-powered, whereas the majority of China's fifty-five submarines rely on diesel propulsion and are therefore more vulnerable to detection. China's nuclear-powered submarines number only around ten. Although the U.S. Navy retains a clear qualitative advantage, the historical significance of ship count in determining naval battle outcomes should not be overlooked. Most crucially, the United States faces a pronounced asymmetry in shipbuilding capacity, and this renders fluctuations in combat vessel numbers particularly consequential.

 

According to the shipbuilding plan submitted by the U.S. Navy in 2025, the number of combat ships capable of launching missiles and torpedoes is projected to decline over the next five to ten years. However, the plan also outlines a rebound beginning in the 2030s, expanding both fleet size and overall firepower. Given that current shipbuilding output reflects prior budgetary allocations, the quantitative dimension of the U.S.-China naval power transition is expected to deepen through at least 2030. In the long term, the 2025 shipbuilding plan sets a target of 381 manned combat ships and 134 unmanned surface and undersea vessels by the 2050s. If fully realized, the U.S. Navy's fleet would expand to 390 combat ships by 2054.

 

Yet whether American industrial capacity and federal resources can support this expansion over the next three decades remains uncertain. The Trump administration's issuance of an executive order on April 2025 indicates a recognition of both the United States' quantitative disadvantage in naval power and its eroding shipbuilding capabilities, and reflects a commitment to address these challenges head-on.

 

IV. The First Line of Naval Defense and the Korean Peninsula

 

As aforementioned, the Trump administration's second-term MAP, announced in early April 2025, mandates that detailed implementation proposals be submitted within a three- to seven-month window. At present, it remains premature to evaluate how effectively the plan will be realized in practice. What is evident, however, is that a quantitative shift in naval power between the United States and China is already underway and is likely to continue through 2030. Depending on how the situation evolves, the United States may need to sustain efforts to address its numerical disadvantage in naval assets well into 2050. The executive order and the April issuance of MAP reflect a clear acknowledgement of this structural challenge and signal an attempt to respond at the level of grand strategy.

 

Historically, leading sea powers have revised or reinforced their first line of naval defense in response to significant shifts in naval power or to changes in alliance structures. In the 1860s, Prime Minister Palmerston strengthened Britain's coastal defenses. In the 1890s, Prime Minister Salisbury adjusted Britain's first line of naval defense in the Mediterranean in response to the Franco-Russian alliance. Similarly, from the late 1930s through the early 1940s, President Franklin D. Roosevelt articulated the United States' defensive perimeter in the Asia-Pacific. In January 1939, he outlined this vision to members of the Senate Armed Services Committee, specifying where the naval defense line should lie across both the European and Asia-Pacific theaters.

 

In this context, how the United States envisions its naval defense line in the Indo-Pacific from 2025 to 2050 will have direct implications for regional stability and crisis management. When considered alongside the ongoing naval power transition between the United States and China, it becomes clear that the Taiwan issue cannot be treated as a matter confined to cross-strait relations alone. For South Korea, which, like Japan, possesses a modern navy and a globally competitive shipbuilding industry, this evolving landscape presents both heightened risk and a critical opportunity to strengthen its geopolitical relevance.

 

Recent remarks by the U.S. Forces Korea (USFK) commander comparing the Korean Peninsula to a strategic "aircraft carrier," as well as unofficial discussions about strategic flexibility within the USFK—despite formal denials by government officials—must be understood in light of the broader naval power transition and the potential reconfiguration of the U.S. maritime defense in Indo-Pacific. It is necessary that Seoul approaches these developments with strategic understanding and formulate policies through which it can contribute meaningfully to regional peace and stability.

 

Meanwhile, North Korea has intensified its naval modernization efforts, particularly in coordination with the expansion of its nuclear capabilities. In April 2025, it launched the new destroyer Choe Hyon. In parallel with the modernization of its conventional fleet, North Korea has worked to expand sea-based platforms capable of supporting second-strike nuclear capabilities. One prominent example is the Hero Kim Kun Ok-class submarine, unveiled in September 2023, which features ten vertical launch tubes, four large tubes for submarine-launched ballistic missiles (SLBMs), and six smaller tubes for submarine-launched cruise missiles (SLCMs). Kim Jong Un described it as a "tactical nuclear attack submarine," signaling a long-term strategy oriented toward SLBM-based deterrence rather than land-based ICBMs. In 2023, North Korea also tested strategic cruise missiles from a newly developed Amnok-class patrol vessel under the observation of Kim Jong Un. The regime continued testing both new and modified strategic cruise missiles into 2024 and conducted two trials of nuclear torpedo launches using unmanned submersibles in January of that year.

 

Seoul is therefore met with the dual challenge of responding to both U.S.-China naval power transition and North Korea's naval modernization and nuclearization, a task that extends through 2030 in the near term and potentially through 2050 in the long term. Although concerns about China's growing quantitative advantage in naval capabilities have been expressed in the United States for several years, Trump 2.0's issuance of MAP suggests that Washington now acknowledges the necessity to address this issue at the level of grand strategy. From 2025 through 2030, and potentially through 2050, South Korea must develop a nuanced understanding of the strategic dilemmas facing the United States and take the initiative in designing a U.S.-ROK shipbuilding cooperation framework that capitalizes on its industrial strengths. As Washington recalibrates the composition and strategic geography of its first line of naval defense, Seoul should explore concrete and feasible ways in which it can contribute to deterrence and the maintenance of regional stability. Concurrently, it must underscore the need for a more integrated extended deterrence posture to address North Korea's advancing nuclear capabilities. ■

 

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■ Inhwan OH  is Senior Research Fellow and Executive Director at EAI.

 

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■ Translated and edited by Chaerin KIM, Research Assistant
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