A number of the essays in this series have grappled with the question of how big a departure Donald Trump’s presidency is from the theory and practice of American foreign policy and international relations more broadly. Having published a book on presidential deception not too long ago, I have been reflecting on this theme with particular reference to Trump’s strained (perhaps broken) relationship with the truth. Trump’s carelessness with the truth is by now well known. The fact-checking site PolitiFact awarded Trump’s statements “Lie of the Year” in 2015. As of 3 February 2017, it had rated fully 69% of his statements either “mostly false,” “false,” or “pants on fire.” By comparison, Hillary Clinton, Trump’s Democratic rival in the 2016 presidential election campaign, was charged with making “mostly false,” “false,” or “pants on fire” claims 26% of the time.