America Against Itself? Internal Domestic Opposition and Trump’s Transatlantic Policy

Since the commencement of Donald Trump’s second presidential term, U.S. foreign and defense policy has entered a renewed phase of transformation, marked by an intensified turn toward unilateralism in transatlantic affairs. This period has been characterized by reduced U.S. commitment to Ukraine, recurrent withdrawal from traditional leadership responsibilities, open criticism of long-standing Western allies, the abandonment of democracy promotion efforts, and heightened financial and political pressure on European partners within NATO. While some observers interpret these developments primarily as responses to structural changes in the international system—most notably the rise of China and the reorientation of U.S. strategic priorities toward the Indo-Pacific—others point to domestic political dynamics as a potential source of constraint on executive foreign policy. This paper adopts a domestic role contestation approach to examine the extent to which internal U.S. domestic actors influence transatlantic policy under the Trump 2.0 administration. Drawing on semi-structured interviews with U.S. foreign and defense policy experts based in Washington, D.C., the paper analyzes the internal dynamics of transatlantic policy formulation and assesses whether domestic opposition meaningfully constrains presidential decision-making. The analysis addresses several research questions: What characterizes the internal decision-making dynamics of the Trump 2.0 administration? Who are the principal actors shaping U.S. transatlantic policy? How do political parties, particularly the Republican Party, position themselves with regard to transatlantic engagement? What forms of domestic contestation have emerged in response to Trump’s foreign policy, and why have these contestations failed to translate into substantive policy change? What role does Congress play in this process, and how does it reflect broader transformations within the U.S. political system? The paper argues that domestic contestation has exerted only a limited influence on the administration’s transatlantic policy. Rather than serving as a meaningful constraint, internal opposition—both across party lines and within the Republican Party—has increasingly converged around preferences for strategic retrenchment, burden-shifting, and selective disengagement from Europe. At the same time, President Trump has consolidated a highly centralized decision-making model that marginalizes traditional institutional and partisan checks on executive authority. Together, these dynamics help explain the resilience of the administration’s transatlantic policy orientation despite ongoing domestic criticism and have significant implications for the future of U.S. foreign policy governance and transatlantic relations.