Doing research for a history of theories of anti-Semitism, I recently read a long-forgotten book published in 1949, “Prophets of Deceit: A Study of the Techniques of the American Agitator.” It decodes Donald Trump more acutely than anything published since his election. Since it is so unknown, it is different from the other titles that are recommended reading these days, like Hannah Arendt’s “The Origins of Totalitarianism” and George Orwell’s 1984.

But unlike those more abstract and literary works grounded in the European experience of fascism and totalitarianism, reading “Prophets of Deceit” locates Trump in a well-worn American tradition, since this is a rhetorical analysis of the anti-Semitic, populist American agitators of the 1930s and ’40s. It was like discovering Donald Trump’s playbook.

We all understand aspects of Trump’s appeal. But like nothing else, “Prophets of Deceit” offers an encompassing analysis. Don’t try to understand the themes of the agitator’s words by their surface content, the author’s countenance. Rather you have to demystify his “secret psychological language,” they explain. Otherwise you might “wave it aside as a kind of mania or a mere tissue of lies and nonsense.”

To plumb the manifest content of the agitator’s expressions, Lowenthal and Guterman open by distinguishing him from the reformer and the revolutionary. They explain how the agitator’s discourse differs from conservatives and liberals. This is because agitators have no specific agenda for change. They seduce by becoming ciphers for resentment and fear. If Liberals and Conservatives speak about what causes social problems and propose solutions, the key to the rhetoric of the agitator is who causes social malaise.

“Social malaise,” is a term of art that Lowenthal and Guterman borrow from sociologists. It encapsulates the objective causes of their listener’s anxiety and disillusionment, which is created by the forces of globalization. The response for many left behind or those who feel threatened is a welter of feelings of distrust and exclusion. These result in a quiver of economic, political, cultural and moral grievances. Those who suffer from malaise are desperate to sling their arrows of outrageous fortune. ...