There is more of a stigma attached to the person who accurately charges another as a Communist than there is to actually being a Communist.

Given that the best scholarly estimates put the Communist body count at around 100 million, and that Joe McCarthy, Martin Dies, and Pat McCarran never killed anyone, the good vs. evil role reversal has to rank as the most amazing feat in the history of propaganda. Too marginalized and numerically insignificant to accomplish this bunko operation on their own, Communists required the unwitting assistance of dupes.

The magic of dupery alchemizes Stalinists into civil libertarians, expropriation into land reform, war-mongering worshippers of Che, Mao, and Ho into peace activists, tyrannies into people’s republics, theft into social justice, and Communists into civil-rights activists.

“To this day, many liberals do not understand that Communists were not their friends,” writes Paul Kengor in his new book, Dupes: How America’s Adversaries Have Manipulated Progressives for a Century. “The Communists used them, and viewed them as gullible, even stupid, and often deserving of contempt for their naivete—a level of naivete that never ceased to amaze the KGB.”

Kengor’s illustrations of dupery in his new book are plentiful. Novelist H.G. Wells touting Stalin as the most honest man he had ever met; limousine leftist Corliss Lamont depicting Russian women’s prisons as happy places where the guards and prisoners sometimes switched roles; and the American Peace Mobilization morphing into the pro-war American People’s Mobilization upon the news of Nazi-Soviet Pact’s violent dissolution all illustrate the phenomenon in action.

Dupes might strike some readers as redundant in the wake of the release of the Venona decrypts, the opening up of the Soviet archives, the declassification of FBI files, the publication of The Black Book of Communism, and the scholarship of Harvey Klehr, John Earl Haynes, Allen Weinstein, Stan Evans, Herb Romerstein, and others. Isn’t this old news?

Alas, the academy has hardly reassessed its verdict on Cold War anti-Communism in light of new evidence. Kengor’s book, too, pertains to dupes—people by definition not officially connected to the foreign apparatus—and not outright agents. And the further events appear in the rearview mirror, the easier it is for ideologues to distort them.

Perhaps most importantly, Kengor places the “dupe” phenomenon beyond its Cold War context, linking it to current events such as Islamic terrorism. In other words, an alienation from America, rather than merely a romantic conception of a foreign ideology, inspires dupes to fall for propaganda. Dupes didn’t disappear with the Berlin Wall.

Don’t let the one-word insult title fool you. Dupes is not the liberal-bashing tome that its title may imply. It spotlights men of the Left who correctly pegged the Soviet Union straight away, such as Woodrow Wilson, who dubbed the Bolsheviks “terrorists” and “barbarians.” There is also a redemptive narrative focusing on liberals who overcame initial gullibility to see the Soviet Union as a great evil. Their ranks included the philosopher John Dewey, the professor-turned-politician Paul Douglas, and an actor named Ronald Reagan.

But most totalitarians found their dupes a reliable bunch. Take the case of Obama mentor Frank Marshall Davis. A clue to his Communism came when he wrote that the Soviet Union was the world’s first colorblind society. Confirmation came when he took the 5th Amendment when questioned about his party membership and admitted joining the Communist Party in a private letter. Informants even produced his membership card number: 47544. Yet, during the 2008 campaign, Newsweek’s Jon Meacham and The New Yorker’s David Remnick ridiculed those raising the issue of the hateful beliefs of Obama’s mentor rather than the hateful beliefs themselves.

Meacham and Remnick would certainly qualify here as dupes. But in certain cases labeling the flunkies for totalitarians “dupes” requires such a suspension of judgment—either on the part of the dupes themselves or on the part of those believing them mere dupes—it causes the reader to wonder who the dupes really are.

Are the dupes the misguided liberals gullibly of parroting the lines fed from Moscow? Or are the dupes their conservative adversaries who gullibly believe that the “dupes” act in good faith?

The hard Left, facing disadvantages of numbers and popular opinion, needs dupes. Perhaps dupes, lacking the courage of their convictions, need the hard Left more.