Is American power in decline? What is the relationship between the perceived decline of American power and the rise of Donald Trump and authoritarian politics elsewhere? Understanding the puzzle of American decline and the world order requires the recognition of how capital and wealth are unjustly distributed, entrenched, and sustained across the society. The core argument here maintains that American decline pertains not only to the decreasing economic vitality underscored by the concrete detrimental effects generated through sharpening material inequality within the US. Rather, decline also constitutes its decreasing appeal and legitimacy as a dominant actor in the international system. This paper contributes to current scholarly and policy debates on American power and authoritarianism in three ways. First, it offers a more holistic conception of American power, particularly by highlighting both its materialist and ideational foundations that co-constitute each other during its periods of ascent, consolidation, and decline. Second, it underscores the mutually reinforcing interdependence of domestic and transnational dimensions of US power. Third, while dominant scholarship on American decline rarely address its implications on international human rights, the paper highlights the uniqueness of the Trump presidency and the emerging authoritarian politics elsewhere: while neoliberalism's detrimental consequences to human rights within and beyond the US constitute a relatively long history, Trump and his allies have abandoned the legitimation tactics that their predecessors had so willingly used. Highlights: • American power constitutes the mutually reinforcing relationship of domestic conditions as well as transformative changes in the international system-an insight often ignored in dominant International Relations scholarship on American decline. • The decline of American power constitutes its decreasing appeal and legitimacy as a dominant actor in the international system. • Examining the status of American power includes its material position and legitimation tactics within the United States and in the international system. • While neoliberalism's detrimental consequences to human rights preceded the Trump administration, currently emerging discourses have abandoned the legitimation tactics that Trump's predecessors had so willingly used.