Last spring, President Donald Trump issued the “Restoring Truth and Sanity to American History” executive order, taking aim at federal parks, monuments, museums, and sites that have cast the United States’s “founding principles and historical milestones in a negative light.” On the Fourth of July this year, the White House published its 162-page “Saving America’s Story,” attacking the Smithsonian Institution directly for “anti-white activism,” “illegal alien activism,” “transgender activism,” and more broadly for adopting “an ideological framework that no longer treats the American story as a shared national inheritance to be taught or celebrated, but as a political instrument to...