In the first year of his presidency, Donald Trump rolled out principled realism as the organizing concept of his foreign policy. But does principled realism have any analytical merit as the underlying precept of Trump’s foreign policy. This paper explores the Trump administration’s use of ‘principled realism’, its contemporary context and its historical antecedents in American history. It finds that Trump uses it an empty slogan despite the essential tension it embodies in American foreign policy between the normative values and national interests. Instead, ‘sovereignty’ is a superior organizing principle of Trump’s foreign policy. In particular, this paper identifies a form of populist sovereignty that is discernible in his public statements throughout 2018. Populist sovereignty is the most distinctive feature of Trump’s foreign policy thinking. It is a doctrine of political action and government priorities that is consonant with his political instincts and that has deep roots in American political culture. Ultimately, populist sovereignty is a much more analytically useful lens through which to understand the foreign policy of Donald Trump.