This study examines how foreign policy under Trump 2.0 has affected transatlantic relations and what consequences this may have for the United States’ position as world hegemon. The Greenland crisis was a unique event in which the central themes of this study coincided. Using the Greenland crisis as a case study, this study analyses the second Trump administration’s transatlantic policy, European responses, and how these can be interpreted as expressions of increased European independence and a weakening of US leadership. The focus of this study is therefore on alliances rather than challengers within hegemonic theory. The analysis draws on hegemonic stability theory, George Modelski’s theory of long cycles, and the concepts of policy drift and bilateralisation. The results show that the Greenland crisis created tensions between the US and Europe, but that the transatlantic alliance endured. However, there were signs of shifting US policy and abandonment of international institutions. From the European side, a dramatic decline in trust in US leadership and an increased willingness to act more independently in foreign and security policy were observed. These changes were interpreted as signs of delegitimation and deconcentration according to the Modelski model. The study concludes that the Greenland crisis was not merely a diplomatic conflict, but also revealed broader changes affecting the US-led international order. The findings further suggest that hegemonic decline does not necessarily have to be drastic or begin with a loss of material power. Rather, alliances, declining trust, and weakening cohesion may be equally important factors.