This sprawling set of 32 short essays is one of the first scholarly efforts to reckon with the Trump administration’s assault on the international liberal order. It is as lively as it is incoherent and inconclusive. As Jervis argues in the introduction, the Trump years provide, if nothing else, a chance for political scientists and historians to test their theories. The essays show that scholars differ on the sources of the crisis—whether President Donald Trump is the cause or the effect—and the scope of it. Realists look to the long-term decline of U.S. power. Others focus on Trump and the institution of the presidency, examining how the national security state constrains its leader. Scholars of international institutions see Trump’s presidency as a test of the theory that institutions and long-standing strategic bargains will prove resilient. Michael Barnett suggests that Trump is so unusual that he escapes the confines of most international relations theory—realist, liberal, or otherwise. The book also features a good debate over the resiliency of the liberal order; like most of the volume’s other discussions, it hinges on each author’s assumptions about the sources of political order and whether domestic political coalitions can be rebuilt around internationalism.