U.S. foreign policy under President Donald Trump marked a significant shift from the liberal internationalist tradition that has guided American diplomacy since the end of the Cold War. The “America First” doctrine forced Trump to decide between expanding U.S. territory aggressively or withdrawing troops right away, which created ongoing confusion about U.S. strategic goals between friends and foes. The research demonstrates that Trump implemented foreign policy through unpredictable actions, which included aggressive behaviour in Latin America and trade policies and his decision to leave international organisations and his disregard for international legal frameworks and his purchase of Greenland. The actions led to damage to U.S. credibility while showing that future administrations would need to solve the permanent challenges which existed.

The Western Hemisphere showed the most evidence of Trump’s excessive authority because he brought back a contemporary version of the Monroe Doctrine, which people call the “Donroe Doctrine.” His government took a confrontational approach toward Venezuela and Cuba, and Nicaragua, through which they used economic penalties and diplomatic cutoffs, and secret military actions to maintain American leadership. The expansionist policy followed the belief that Latin America should remain under U.S. control, but it created potential conflicts with neighbouring countries and negative reactions from them. The situation made people believe that the United States had gone back to its historical practice of dominating the hemisphere instead of accepting the new reality, which included multiple powers operating together in the region.

Trump used economic coercion through his trade wars, which he initiated against China and the European Union, and Canada and Mexico. The administration used its maximum trade power through heavy tariff imposition, and it started trade wars with both friendly and hostile nations, which created worldwide market instability while damaging existing international trade agreements. The United States adopted unilateral foreign policy approaches, which included security policy changes that involved Trump supporting individual agreements instead of international organisations, and he forced NATO members to pay more for their defence costs while using military force in Middle Eastern territories. These actions together created an impression that the United States was exceeding its authority because it sought to enforce its decisions without shared agreement, which resulted in damage to its established alliances.

Trump made Greenland acquisition his goal to achieve his mission of expanding American territory. In 2019 and again during his second term, he pursued the idea of acquiring Greenland, an autonomous territory of Denmark, citing its strategic importance in the Arctic. The proposed deal caused Europe and Copenhagen to experience mass public outrage because Prime Minister Mette Frederiksen stated Greenland remained unavailable for purchase. The NATO leaders stated that any military action to control or occupy the island would break up the alliance because some members predicted it would destroy NATO completely. The diplomatic opposition Trump faced during his Greenland pursuit made the United States appear as an imperial power, which damaged European-American relations while China and Russia increased their Arctic territorial activities.

The foreign policy of Trump included two distinct approaches, which involved both withdrawal from international affairs and a practice of staying away from global matters. His decision to leave the Paris Climate Agreement and his refusal to join the World Health Organisation during COVID-19, and his doubts about NATO obligations demonstrated his purposeful withdrawal from international organisations. The United States’ exit from its international duties caused its partners to lose confidence in the country while simultaneously damaging the international framework, which needs countries to work together. The “America First” rhetoric made sovereignty and domestic interests more important than global leadership, which led people to believe Washington was abandoning its position as guardian of the international system. The President’s refusal to participate in nation-building activities and his decision to avoid extended military deployments demonstrated his support for an isolationist foreign policy because he wanted to decrease U.S. military forces abroad and minimise international involvement.

A third aspect of Trump’s foreign policy was its disregard for international law. His administration pulled the United States out of multiple international organisations and UN agencies, which resulted in damage to multilateral legal systems. The European leaders, together with legal experts, criticised the operation to capture Venezuelan President Nicolás Maduro because it occurred without United Nations approval, which they viewed as a violation of international law. The method is based its approach on the “might makes right” which employs unilateral power politics to disregard international norms. Trump’s decision to ignore international law made his foreign policy actions less valid while he helped break down the international legal framework which the United Nations established after World War II.

The upcoming obstacles will be extremely difficult to overcome. The foreign policy of Trump showed inconsistent behaviour because he alternated between expanding U.S. influence and withdrawing from international affairs, which produced confusion among allies while strengthening the position of hostile nations. The United States faced relationship damage and economic instability because of its excessive actions in Latin America and its trade policies, and its Greenland policies. The United States lost its ability to create international standards because it withdrew from global organisations. The United States lost its position as a defender of international rules because it failed to respect international law, which allowed China and Russia to establish their own governance systems. Future administrations need to establish trust with the public while they demonstrate leadership, and they need to find ways to handle internal political conflicts that affect their ability to fulfil their international duties. The main difficulty stems from needing to show both strong commitment and proper moderation when protecting national sovereignty and working with others to achieve common goals during an uncertain time for American leadership.

Future administrations need to restore U.S. foreign policy credibility through their commitment to international agreements and their defence of international legal standards while they execute strong regional policies and work together with other nations on global issues. The methods Trump used to handle foreign policy relations between nations resulted in damaged international partnerships and reduced American influence within the rules-based global system, while creating unfavourable views about America throughout international territories. The damaged reputation has made American citizens more vulnerable because it has reduced international friendship and raised security threats during this period of rising international tensions. The United States needs to unite its diplomatic efforts with controlled actions to avoid both independent foreign policy mistakes and complete withdrawal from international relations. The United States needs to establish trust with its allies through balanced foreign policy actions, which will protect its citizens and maintain its position as a dependable leader of the international system.

The opinions expressed in this article are the author’s own.

References

Lissner, R., Freeman, W., Sacks, D., Fix, L., Cook, S. A., Gavin, M., & Stares, P. B. (2025/2026). Unpacking Trump’s norm-breaking National Security Strategy and what it means for U.S. foreign policy. Council on Foreign Relations. 

Atlantic Council. (2025/2026). Experts react: What Trump’s National Security Strategy means for U.S. foreign policy. Atlantic Council. 

Sheehan, L. (2026). The world minus one: U.S. foreign policy and the erosion of the international order. Foreign Policy, Winter 2026 issue.