Dinesh D’Souza knows the value of a good controversy. After all, he has made a career of lobbing ideological hand grenades. In 2010, for instance, he published a book and an article in Forbes arguing that Barack Obama had embraced his father’s anticolonial fervor and was intentionally squandering America’s influence to put it on equal footing with the developing world. Critics were aghast. The Columbia Journalism Review called the Forbes piece “a fact-twisting, error-laden piece of paranoia” and a “singularly disgusting work,” while the conservative Weekly Standard assailed D’Souza’s “misstatements of fact, leaps in logic, and pointlessly elaborate argumentation.” Former...