The most important thing to know about the Trump administration’s defense of its hotly contested use of tariffs to bring allies and opponents to heel is not that it is a novel and unprecedented legal argument but rather a full-throated articulation of the campaign themes that got the president elected – in both 2016 and 2000. In its legal documents, and in the oral arguments that took place before the Supreme Court Wednesday, the Trump administration paints a picture of America under siege. Once thriving industrial towns in the Midwest hollowed out. Factories dismantled as supply chains have been moved...