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Is the Second Trump Administration’s NSS the Starting Point of a Post-Hegemonic Era? |
| December 30, 2025 |
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Sang Hyun LeePrincipal Research Fellow, Sejong Institute | shlee@sejong.org
- The return of the Trump administration, Russia’s invasion of Ukraine, and the expansion of China’s influence indicate the end of the relative peace among major powers that had persisted for roughly 30 years after the end of the Cold War. The world has already entered the early stage of a “New Cold War,” and the future trajectory of the international order remains highly uncertain. What is clear is that the rules based international order established under U.S. leadership after the Second World War is increasingly difficult to sustain, and the international system has reached a major inflection point. The Trump administration’s 2025 National Security Strategy(NSS) may serve as a signal marking the full onset of these changes. The world now appears to be entering a transitional period from an era of U.S. hegemony to a post hegemonic era.
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The Trump 2.0 National Security Strategy(NSS) represents a highly unconventional departure from the NSS documents issued by previous administrations. Signs of this departure were already evident in the first Trump administration’s 2017 NSS. That document attracted attention as a national security strategy reflecting the Trump administration’s “America First” approach, which had been central to President Trump’s election campaign calling for the restoration of American greatness. The second Trump administration’s NSS has returned with an even more forceful America First orientation, buoyed by strong support from the “Make America Great Again(MAGA)” political base.
The purposes of issuing a U.S. National Security Strategy can generally be summarized as follows. First, it serves to share the administration’s national security vision with Congress and to justify associated budgetary requests. Second, it functions as a tool for communicating the administration’s strategic vision to relevant foreign partners and counterparts. Third, it is intended to present the president’s agenda to domestic supporters and political constituencies and to secure sustained and coherent backing. Fourth, it aims to build internal consensus among executive branch agencies responsible for foreign and defense policy. Fifth, it seeks to elevate and reinforce the overall agenda and messaging of the president.
When assessed against these purposes, the Trump 2.0 National Security Strategy stands in marked contrast to the NSS documents of previous administrations. The 2025 NSS can be characterized as a highly ideological and political document, featuring the institutionalization of America First, a hegemonic strategy centered on economic security, expanded demands for allied burden-sharing, reduced commitments in the Middle East and Europe, and a reinforced focus on Asia. At the same time, it places the restoration of U.S. domestic capacity at the center of strategy, identifies China as a long term and systemic competitor, and proposes a reprioritization that reflects the practical constraints of the international system. In this sense, the document can also be assessed as marking a strategic turning point.
The core elements of the Trump 2.0 NSS may be summarized as follows. Its underlying worldview can be characterized as a restoration of “peace through strength.” Compared with past NSS reports, it places greater emphasis on power over norms, transactions over alliances, and national interest over values. It also displays a pronounced skepticism toward the liberal international order. A rules- based order centered on norms and institutions is viewed as idealistic and as imposing excessive burdens on the United States. The document reflects President Trump’s long held view that the United States has been ripped off by both allies and adversaries. It is grounded in a realist perspective that sees the international system as an arena of power politics. In this context, the United States focuses on institutionalizing an America First approach that prioritizes national interests. Alliances, multilateral institutions, and norms are to be maintained only insofar as they serve U.S. interests, and a transactional approach is reinforced across strategic, economic, and technological domains.
One of the most notable features of the 2025 NSS is its shift in U.S. strategic focus back to the Western Hemisphere and its invocation of a reinterpreted Monroe Doctrine described as the “Trump Corollary.” This suggests a renewed “Western Hemisphere first” orientation and intensified competition over spheres of influence. Perhaps most striking is its relationship with Europe. The 2025 NSS strongly emphasizes “alliance fatigue” with Europe and calls for greater European autonomy. It criticizes European allies as placing burdens on the United States in areas such as defense spending, migration, and regulation of expression, while also referring to the civilizational and political restoration of Europe and describing Europe as facing a “civilizational decline.”
Assessments of the 2025 NSS reflect both positive and negative perspectives. Some analysts view the document favorably for centering U.S. policy on tangible national interests and capabilities (economic strength, military power, and technological capacity) while attempting to reduce the burdens associated with assuming responsibility for the global order in the post-Cold War environment. In this view, the era in which the United States “held up the international order like Atlas” has ended. By recalibrating strategic priorities toward the Middle East, Asia, and the Western Hemisphere, the NSS is seen as reflecting a reassessment of decades of perceived overextension and as shifting toward a realist approach focused on sustainable U.S. security rather than on the preservation of hegemony. Measures such as reductions in overseas troop deployments, decreased involvement in the Middle East, and an emphasis on burden-sharing and burden-shifting are interpreted as efforts to move away from excessive defense expenditures and prolonged military interventions.
Conversely, the Trump 2.0 NSS has also been criticized as excessively personalized in its strategic orientation. Some analysts view the document not merely as a statement of foreign and security policy, but as a a highly partisan, inward looking document that reads as a personal manifesto. In this interpretation, it represents less a national strategy for the United States as a whole than a continuation of the political trajectory of the second Trump presidency. The NSS is seen as signaling a reduced willingness to sustain the postwar U.S. role as defender of global democracy and manager of the international order. With regard to Europe, the document employs language referring to identity erosion and civilizational decline, and includes passages that appear to signal tacit support for or encouragement of right wing and nationalist political forces within Europe. Such elements have generated concern among established allies about a potential shift in U.S. policy toward more right leaning or far right orientations.
The discussion below focuses on several issue areas concerning the international order as reflected in the Trump 2.0 NSS.
First, the Trump NSS clearly signals a change in the character of the international order. A competitive order based on power politics is likely to become more prevalent in place of a liberal or rules-based international order. Agendas that have traditionally occupied a central place in U.S. foreign policy, such as democracy, human rights, and multilateralism, are likely to recede to secondary status, leading to a retreat of norm centered order. National interests, national power, and transactional outcomes are expected to take precedence over international norms, with greater emphasis placed on order maintained through deterrence and negotiation rather than on a rules based order. As diplomatic focus shifts from value based diplomacy to outcome-based diplomacy, the moral dimension of the international order is likely to fade. In this context, allies and partners are also expected to be evaluated more on the basis of contributions and burden-sharing than on shared values. This development resembles not the dissolution of the liberal international order but rather its functional weakening.
Second, great power relations define competition with China and Russia as the principal challenge. In particular, U.S.–China relations have shifted from managed competition to long term and structural adversarial competition. China is no longer viewed merely as a “challenger” but as a systemic competitor and strategic threat across technological, military, industrial, and financial domains. The approach to competition with China involves avoiding direct large scale confrontation while maintaining sustained pressure. Decoupling or strengthened de-risking is likely to continue in areas such as core technologies, artificial intelligence, semiconductors, and energy. U.S.–China rivalry is thus expected to solidify into a persistent state of competition without a clear phase of relaxation. In contrast, Russia is perceived less as a long term systemic competitor than as a regional military threat.
Third, the global economic order is likely to see a slowdown or reversal of globalization, alongside growing bloc formation and the normalization of a transactional economic order. Economic security is expected to take precedence over free trade, and supply chains are likely to prioritize reliability and alliance ties over efficiency. As a result, the process of globalization, which had contributed to rapid global economic growth, may give way to the institutionalization of “slobalization,” referring to a slowdown, stagnation, or retreat of globalization. The influence of multilateral institutions such as the WTO and IMF, which have supported the free trade system, is likely to weaken further. In a transactional economic order, allies are not exempt. The United States under Trump is expected to apply a package based assessment of allies and partners, weighing market access, security contributions, and political loyalty. The global market is therefore likely to fragment into multiple politicized markets rather than remain a single integrated space.
Fourth, the alliance order is likely to evolve from value-based alliances to contract-based alliances centered on costs and roles. Alliances may no longer function as communities that automatically share defense responsibilities, but rather as security arrangements defined by explicit contributions, burdens, and roles. This shift sends a clear signal to traditional U.S. allies such as South Korea, Japan, and European countries. These allies face pressure to increase defense burden-sharing and to expand strategic autonomy, particularly in areas such as nuclear and missile defense and industrial capacity. Allies are increasingly expected to function not as recipients of U.S. support but as partners that reduce the U.S. burden. While the alliance system is likely to be maintained, the quality of trust within it may become more unstable.
Fifth, the nuclear order and security environment are likely to shift from a focus on strategic stability to one of deterrence competition, with the NPT formally maintained but its substantive binding force weakened. As perceptions of nuclear and missile threats change, discourse on arms control and strategic stability may recede, while emphasis grows on achieving superiority and ensuring the credibility of deterrence. Extended deterrence provided by the United States to allies and partners may increasingly be treated as transactional, linked to political, military, and financial considerations rather than automatically provided.
Sixth, as the United States steps back from its position as a hegemonic power, a decline in global governance appears likely. The status of international organizations such as the United Nations, WHO, and WTO, which have formed pillars of the post-WWII order, is expected to diminish, and multilateralism may become more peripheral. The United States is likely to use international institutions selectively when they serve its interests. This suggests a persistent possibility of U.S. departure from the rules-based international order. Order management is also likely to shift from institution centered approaches toward bilateral negotiations and balances of power. With the weakening of the rules-based order and global governance, the world may increasingly move toward a state of “managed disorder.” The world envisioned in the Trump 2.0 NSS is thus one in which order is shaped not by rules but by power and transactions, requiring states to redesign their strategies on the premise of self reliance. -
The changes in the international order discussed above suggest, in broad terms, a transition from the U.S.-led hegemonic order established after the Second World War toward a new multipolar order as that hegemonic structure erodes. If a slogan were to be attached to the Trump administration’s new National Security Strategy(NSS), it might be “Make America a Regional Power Again.” The document opens with a pointed critique of U.S. foreign policy over the past several decades, during which the United States, as a global hegemon, pursued its interests worldwide, promoted globalization, embraced international institutions, and assumed extensive global burdens.1)
The Trump NSS argues that the United States should define its national interests much more narrowly. While acknowledging that certain interests remain in Europe and Asia, it contends that fundamental interests lie in the Western Hemisphere. In doing so, it invokes a “Trump Corollary,” which closely resembles the Monroe Doctrine and the Roosevelt Corollary articulated by Theodore Roosevelt. The Trump Corollary refers to an expansion of Monroe style thinking centered on isolationist principles. Secretary of State Marco Rubio has recently explained that “America First” means giving primary attention to the region in which the United States resides.
Fareed Zakaria argues that it is misguided to confine the global scope of a superpower such as the United States, which exerts extensive influence worldwide, to a Monroe era perspective. A foreign policy that prioritizes America’s backyard would focus Washington’s attention on one of the least economically significant regions of the world. Moreover, the context of 1823, when President James Monroe proclaimed the Monroe Doctrine, differs markedly from the present. At that time, the United States was a relatively weak newly independent state advocating principles of anti colonialism and non intervention, urging European powers to recognize the independence of Latin American states and refrain from colonization.
Today, however, the United States is the only country with the capacity to sustain the international system in a stable manner. If the United States withdraws, a power vacuum would emerge, and less responsible major powers could fill the void. A century ago, when the United States avoided responsibilities it was capable of bearing, the international system deteriorated and ultimately led to the Second World War. Although other stabilizing forces exist today, if the United States focuses only on its immediate neighborhood, the world could drift toward instability and disorder without clear leadership.
How, then, might the post-hegemonic international order evolve? T.V. Paul of McGill University describes the character of the new Cold War as a “multipolar-multiplex Cold War.” Compared with the earlier Cold War, the likelihood of direct confrontation among major powers such as the United States, China, and Russia is significantly lower, but these powers are involved in proxy and indirect conflicts across multiple regions. Ideological confrontation is far more diluted than in the earlier Cold War, and despite pressures toward deglobalization, economic interdependence remains relatively high.2)
Another characteristic is the rise of middle powers and regional powers such as India, Brazil, Saudi Arabia, and Indonesia. These states seek to expand autonomy and strategic space while avoiding firm alignment with any single bloc. Cross cutting institutional frameworks such as the G20, BRICS, and the SCO complicate rigid Cold War style bipolar division. Many states that are not major powers pursue survival through hedging strategies amid great power strategic competition. T.V. Paul characterizes this order as a multipolar and multiplex Cold War order. If the gap between the United States and China widens significantly, this order could evolve into a bi-multipolar structure.
One factor driving the emergence of this complex order is intensifying great power competition and the erosion of the liberal international order. Looking further back, the U.S. “war on terror” contributed to regional instability and began to expose the limits of unipolar hegemony. Russia’s invasion of Ukraine and annexation of territory directly violated the fundamental principle of territorial sovereignty under international law. China has sought to expand influence through geo economic strategies centered on the Belt and Road Initiative(BRI), while the United States has struggled to present an effective alternative.
These trends are reinforced by the Trump administration’s neo-imperial and neo-mercantilist approach. The administration has employed tariffs, trade, investment, and security as transactional and coercive tools and has shown a strong tendency to weaken or dismantle the liberal international order. In diplomacy, transactional criteria prioritizing U.S. interests and status restoration are applied over ideology or values. Another driver of change is the strategic agency of non-great powers. Middle powers and regional powers are no longer passive actors. Historically they have sought to leverage, adjust, and constrain great power competition, and their strategic autonomy is expanding further today.
Amitav Acharya has offered a theoretical framework to explain the decline of the Western-centered “liberal international order” and the plural and decentralized world order that may follow.3) His basic point of departure is the question of whether the liberal international order was ever truly universal. Acharya argues that while the postwar order has often been described as a U.S.-led liberal order, in practice it reflected a Western experience generalized into a biased narrative that did not sufficiently incorporate the histories, norms, and institutions of the non Western world. In his view, the crisis of the so called rules-based international order today stems not only from the relative decline of U.S. hegemony but also from design flaws and limited representativeness within the order itself.
Surveying five millennia of world history, Acharya shows that international orders enabling cooperation and peace among states existed long before the rise of the West. From ancient Sumer, India, Greece, and Mesoamerica through the medieval caliphates and Eurasian empires to the modern era, he demonstrates that humanitarian values, economic interdependence, and norms governing state behavior have appeared globally over thousands of years. History suggests that order can persist even as Western dominance recedes. The end of Western dominance may provide opportunities for non Western states to gain greater voice, power, and prosperity. Rather than fearing the future, Western countries are encouraged to learn from history and work with the rest of the world to build a more equitable order. His work offers an explanation of how world order has evolved and why it may endure despite Western decline.
In this perspective, the key concept is a Multiplex World Order. A multiplex order is characterized by the absence of a single set of rules or a single leader. In this order, not only the United States and China but also middle powers, regional organizations, and non Western states participate in shaping order. Instead of one dominant screen centered on U.S. norms, multiple screens operate simultaneously, with diverse norms, institutions, and orders coexisting. Pluralism rather than universalism is emphasized. This is not merely a post-American order but a post-Western order in which non-Western actors participate more fully. States are expected to draw selectively on different norms and institutions depending on circumstances and interests.
Acharya cautions against linking U.S. hegemonic retrenchment directly to arguments about systemic collapse. A relative decline in U.S. influence does not automatically lead to anarchy or disorder. Instead, regional orders are likely to be strengthened. Mechanisms such as ASEAN, the African Union, and regional arrangements in the Middle East and Latin America suggest that global governance may function in more decentralized, overlapping, and layered forms. From this perspective, the international order is undergoing reordering rather than collapse. In this process, non Western states are redefined not as rule-takers but as rule-takers. For example, historical norms in Asia and Africa rooted in colonial experiences, such as principles of sovereignty and non intervention, have contributed to the global diffusion of regional practices and institutions. The future of international order is thus being shaped not only in Washington and Brussels but also in Jakarta, New Delhi, and Addis Ababa. -
The evolution of the international order in the post-hegemonic era carries significant strategic implications for non-major powers states such as South Korea.
First, many observers express concern about disorder in a post-hegemonic international order. However, it is not necessary to equate the retrenchment of U.S. hegemony with the collapse of a rules-based order or with an era of chaos. Order existed even before the period of U.S. hegemony. In fact, some form of order has always existed throughout human history. Accordingly, the departure of U.S. hegemony should not be viewed with excessive alarm. What has increased, however, is the need to prepare for greater strategic complexity arising from the coexistence of multiple chessboards, including security and economic orders. South Korea should therefore prepare a comprehensive national strategy that integrates both security and economic considerations.
Second, the post-hegemonic era may present opportunities for expanding the agency of middle powers. A world divided into spheres of influence among the United States, China, and Russia presents both challenges and opportunities for countries that are not major powers. These states will face pressures of alignment, as well as heightened risks of abandonment and entrapment. At the same time, this environment may offer opportunities to strengthen middle power agency. As global hegemonic order gives way to a system in which regional orders gain greater importance, middle powers at the regional level may find opportunities to expand their influence. South Korea, already recognized internationally as a middle power, can leverage this position to pursue a pragmatic foreign strategy centered on national interests.
Third, like minded countries should work toward sustaining a rules based order and a free trade system even in the absence of U.S. leadership. The future international order may resemble a “G-minus Era” in which major powers show limited interest in maintaining order. For countries that are not major powers, a rules based order remains comparatively more stable and predictable. One of the most viable paths forward is for like minded states to develop new rule systems. Although an anarchic trade system is undesirable, a full return to the previous status quo may not be feasible. As an alternative, the global economy could move toward open plurilateralism, which is more flexible and somewhat smaller in scope than a fully multilateral rules-based trade system.4) Multilateral cooperation remains possible even without hegemonic U.S. leadership. However, a multilateral international order favored by such states will be sustainable only if its core members, such as Europe, Japan, and South Korea, act proactively and in concert.5)
| Shifts in the International Order as Reflected in the Trump National Security Strategy
| The Character of the International Order in the Post-Hegemonic Era
| What Should South Korea Prepare for in the Post-Hegemonic Era?
1) 파리드 자카리아, “우려스런 트럼프의 먼로독트린 향수,” 『서울경제』, 2025.12.26. (https://www.sedaily.com/NewsView/2H1VODCIKP/GG03).
2) T.V. Paul and Markus Kornprobst (Eds.), The New Cold War and the Remaking of Regions (Georgetown University Press, 2025)
3) Amitav Acharya, The Once and Future World Order: Why Global Civilization Will Survive the Decline of the West (Basic Books, 2025).
4) Michael B. G. Froman, “After the Trade War Remaking Rules From the Ruins of the Rules-Based System,” Foreign Affairs, September/October 2025 (https://www.foreignaffairs.com/united-states/after-trade-war-michael-froman).
5) Ngaire Woods, “Order Without America: How the International System Can Survive an Hostile Washington,” Foreign Affairs, May/June 2025 (https://www.foreignaffairs.com/united-states/donald-trump-order-without-america-ngaire-woods).
※ The contents published on 'Sejong Focus' are personal opinions of the author and do not represent the official views of Sejong Institue
