Mr. Stanley begins by offering a definition of propaganda that extends beyond dictionary descriptions of biased or misleading information used to promote a particular political cause or point of view. “Propaganda is characteristically part of the mechanism,” he writes, “by which people become deceived about how best to realize their goals, and hence deceived from seeing what is in their own best interests.” This is achieved by various time-tested means — by appealing to the emotions in such a way that rational debate is sidelined or short-circuited; by promoting an insider/outsider dynamic that pollutes the broader conversation with negative stereotypes of out-of-favor groups; and by eroding community standards of “reasonableness” that depend on “norms of mutual respect and mutual accountability.”

Image Jason Stanley Credit... David Weinstock

In an opinion piece for The New York Times just before this year’s presidential election, Mr. Stanley wrote that Donald J. Trump “engaged in rhetorical tactics unprecedented in recent American electoral history”: that he “repeatedly endorsed obviously false claims” and made many “odd comments, retractions, semi-retractions and outright false statements” — and in the process promoted a willfully dystopian (and distorted) portrait of America as a dysfunctional country reeling from violence and crime that needed him to restore law and order.

Denouncing Mr. Trump “as a liar,” Mr. Stanley argued, “misses the point of authoritarian propaganda altogether. Authoritarian propagandists are attempting to convey power by defining reality. The reality they offer is very simple. It is offered with the goal of switching voters’ value systems to the authoritarian value system of the leader.”

In this volume (originally published in hardcover in 2015), Mr. Stanley does not grapple directly with Mr. Trump’s rhetoric, or the role that “fake news” played in the 2016 election. But his book does provide some useful insights into the dangers of propaganda — and its reliance upon mangled facts; false claims; and reductive, Manichaean storytelling. He observes that demagogic speech in democracies often uses language that purports to support liberal democratic ideals (liberty, equality and objective reason) in “the service of undermining these ideals.” He points out that propaganda frequently raises fears that are likely to curtail rational debate — for instance “linking Saddam Hussein to international terrorism” after Sept. 11 — and that it may play upon deeper prejudices toward ethnic or religious groups that rob “us of the capacity for empathy toward them.”

In a section on derogatory language, Mr. Stanley writes that “standard slurs for ethnic groups are too widely recognized as slurs to occur in political debate in a liberal democracy” (though “as liberal democracy breaks down, as in the case of modern-day Hungary,” he adds, “explicit slurs become more acceptable”). At the same time, “apparently innocent words” or phrases — like welfare, work ethic, illegal immigrant — can take on negative connotations as they become “imbued, by a mechanism of repeated association, with problematic images or stereotypes.”