Ever since Donald Trump first became U.S. president, in 2017, commentators have searched for an adequate label to describe his approach to U.S. foreign relations. Writing in these pages, the political scientist Barry Posen suggested in 2018 that Trump’s grand strategy was “illiberal hegemony,” and the analyst Oren Cass argued last fall that its defining essence was a demand for “reciprocity.” Trump has been called a realist, a nationalist, an old-fashioned mercantilist, an imperialist, and an isolationist.