Title: Donald Trump’s “America First” Policy and the Erosion of the Post-World War II Global Order
Abstract
This paper examines the profound impact of Donald Trump’s “America First” foreign policy on the post-World War II global order. By analyzing his unilateral actions, rejection of multilateralism, and aggressive military posturing, the study argues that Trump’s presidency has systematically dismantled the international structures established by the United States after 1945. The paper explores how Trump’s ideological alignment with realpolitik and his disregard for traditional statecraft have destabilized global governance frameworks, redefined U.S. leadership, and challenged the liberal internationalist ethos that underpinned the post-Cold War era.
Introduction
Since its inception after World War II, the United States has been the principal architect and guardian of a liberal international order characterized by multilateral institutions, collective security frameworks, and a commitment to democratic values. This order, formalized through organizations such as the United Nations (UN), the North Atlantic Treaty Organization (NATO), and the World Trade Organization (WTO), aimed to promote global stability, peace, and cooperation. However, since his election in 2016, and particularly in the early 2020s, U.S. President Donald Trump has fundamentally challenged these norms through his “America First” agenda. This paper contends that Trump’s foreign policy—defined by unilateralism, militarism, and ideological intransigence—has fractured the foundations of the post-1945 global order, with far-reaching implications for international relations.
- Unilateralism and the Rejection of Multilateralism
Trump’s most visible disruption to the post-World War II order has been his systematic withdrawal from multilateral institutions. During his second term, the administration exited over a dozen UN-related bodies, including the World Health Organization (WHO) and the UN Human Rights Council, framing these moves as a defense against “globalist projects.” This rhetoric, echoed by Secretary of State Marco Rubio, who dismissed the UN as a vehicle for the discredited “End of History” liberal project, signaled a rejection of institutional multilateralism as a tool for global governance.
The U.S. role in founding these institutions was predicated on the belief that collective action could prevent global conflicts and promote shared prosperity. However, Trump’s policy has framed multilateralism as a mechanism of U.S. subordination, most notably when he criticized NATO as “obsolete” and threatened to abandon its collective defense clause. By prioritizing unilateral solutions, Trump has eroded the credibility of U.S. leadership in global governance. For instance, the unprovoked military intervention in Venezuela—a nation under democratic rule albeit with contested legitimacy—exposed the gap between American rhetoric and practice, undermining the moral authority of institutions like the United Nations.
- Aggressive Military Posturing and Unilateral Interventions
Trump’s foreign policy has been marked by a willingness to use or threaten force in ways that diverge sharply from traditional U.S. statecraft. The January 3, 2025 attack on Venezuela, which resulted in over 100 civilian deaths and the abduction of President Nicolás Maduro, exemplifies this approach. While U.S. leaders in the past often justified military actions through the lens of democratic promotion or collective security (e.g., the 2003 Iraq invasion), Trump’s Venezuela campaign lacked such pretensions. Instead, it was framed as a direct challenge to regional anti-Americanism, with the U.S. seeking to install a pro-business interim government aligned with American interests.
This pattern continued with Trump’s threats of military action against Iran, a longtime U.S. adversary. As Iranian protests against clerical rule intensified, Trump issued bellicose warnings, leveraging force not as a last resort but as a negotiating tool. Similarly, his repeated calls to annex Greenland from Denmark—a NATO ally—highlighted a disregard for sovereignty and alliance cohesion. These actions, often reversed after diplomatic pressure (e.g., retracting military threats to Mexico and Colombia), underscored Trump’s transactional, ad hoc foreign policy, which prioritized immediate U.S. interests over long-term strategic consistency.
- Ideological Shift: Realpolitik and the Rejection of Liberal Internationalism
Central to Trump’s foreign policy is his ideological embrace of realpolitik, encapsulated in White House Deputy Chief of Staff Stephen Miller’s declaration that “we live in a world… governed by strength, force, and power.” This philosophy contrasts sharply with the liberal internationalist ethos that has guided U.S. foreign policy for decades. By discarding the moral high ground—a concept central to promoting democracy and human rights—Trump has legitimized a self-interested, zero-sum approach to global diplomacy.
The administration’s handling of domestic issues, such as the anti-immigrant campaign, further reflects this realpolitik worldview. Trump’s response to the 2025 Minneapolis incident, where a far-right agent killed a motorist in a racially motivated attack, saw the administration reject calls for proportionality or international solidarity. Instead, Vice-President J.D. Vance declared that the U.S. would “take back control” from “globalist elites,” aligning domestic policies with a broader anti-establishment, nationalist agenda. Such stances have weakened America’s role as a champion of universal values, replacing it with a pragmatic, transactional leadership model.
- Domestic Policy as Foreign Policy: The “America First” Doctrine
The “America First” ideology, which underpins Trump’s foreign policy, is not confined to international relations but is mirrored in domestic governance. Trump’s administration framed immigration controls as a matter of national survival, using rhetoric that conflated internal and external threats. This approach has externalized the U.S. brand as one of exclusion and strength, influencing diplomatic engagements. For example, Trump’s refusal to apologize for the Venezuela attack, despite civilian casualties, underscored a lack of adherence to “international niceties,” as Miller articulated.
This domesticated realpolitik has also strained alliances. The Greenland controversy, for instance, tested NATO unity, with Denmark’s government resolutely defending its sovereignty. By treating allies as negotiable and adversaries as manageable threats, Trump has further destabilized the alliance systems critical to the post-war order.
- Implications for the Global Order
The ramifications of Trump’s policies are profound. First, the retreat from multilateralism weakens global governance structures, creating a vacuum in international crises management. Second, the normalization of force as a policy tool undermines norms of state sovereignty and diplomatic resolution. Third, the erosion of U.S. moral authority may embolden revisionist powers, such as China and Russia, to challenge the existing order without restraint.
However, some scholars argue that the post-1945 order was already fraying before Trump. The 2003 Iraq War, for instance, showcased U.S. hypocrisy in bypassing the UN. The difference lies in Trump’s unapologetic embrace of self-interest and his rejection of even the performative aspects of liberal internationalism. This shift risks a multipolar world where power dynamics dominate over cooperation, with no clear arbiter to enforce shared norms.
Conclusion
Donald Trump’s “America First” policy has irrevocably altered the trajectory of U.S. foreign relations. By dismantling multilateral structures, normalizing unilateral force, and prioritizing realpolitik, Trump has shattered the post-World War II order’s foundational principles. While his critics warn of global instability and the erosion of democratic values, proponents argue that his approach restores a more honest, pragmatic U.S. leadership model. Irrespective of perspective, Trump’s presidency represents a tectonic shift in international relations—one that redefines the balance of power and reconfigures the rules of global governance for the 21st century.