Preston Damsky is a law student at the University of Florida. He is also a white nationalist and antisemite. Last fall, he took a seminar taught by a federal judge on “originalism,” the legal theory favored by many conservatives that seeks to interpret the Constitution based on its meaning when it was adopted. In his capstone paper for the class, Mr. Damsky argued that the framers had intended for the phrase “We the People,” in the Constitution’s preamble, to refer exclusively to white people. From there, he argued for the removal of voting rights protections for nonwhites, and for the...