From nearly the beginning of the United States, Americans have used arches to make visual arguments about the nation’s ideals. When George Washington arrived in Philadelphia after his election as president in 1789, he was welcomed by an arch of laurels and evergreens. Among its erectors was the painter Charles Willson Peale, who also made a 46-foot arch of painted canvas and wood that briefly stood in front of the city’s President’s House, where Washington would live for the bulk of his two terms. Arches, a form that linked the new North American nation to the classical Europe that had informed the Founding Fathers’ republicanism, helped give the U.S. a legitimizing past. Ever since, artists have used arches to celebrate U.S. republicanism, including to alert us to the plutocratic and autocratic forces that might corrupt it. In other words, they have issued warnings against the very qualities that the latest proposed arch—which President Trump wants to build across the Potomac River from Washington, D.C.—would embody. Trump’s arch would fill a traffic circle between the west …