Demagogy or demagoguery (Ancient Greek δημαγωγία, from δῆμος dēmos "people" and ἄγειν agein "to lead") is a strategy for gaining political power by appealing to the prejudices, emotions, fears and expectations of the public—typically via impassioned rhetoric and propaganda, and often using nationalist, populist or religious themes. What qualifies as demagogy has been the subject of debate and ambiguity since Aristophanes first used the term, in reference to Cleon.
20th-century American social critic and humorist H. L. Mencken defined a demagogue as "one who will preach doctrines he knows to be untrue to men he knows to be idiots."
As George Bernard Shaw said:
But though there is no difference in this respect between the best demagogue and the worst, both of them having to present their cases equally in terms of melodrama, there is all the difference in the world between the statesman who is humbugging the people into allowing him to do the will of God, in whatever disguise it may come to him, and one who is humbugging them into furthering his personal ambition and the commercial interests of the plutocrats who own the newspapers and support him on reciprocal terms.
Political leadership in the form of the free 'demagogue' who grew from the soil of the city state is of greater concern to us; like the city state, the demagogue is peculiar to the Occident and especially to Mediterranean culture. Furthermore, political leadership in the form of the parliamentary 'party leader' has grown on the soil of the constitutional state, which is also indigenous only to the Occident.
Though this definition emphasizes the use of lying and falsehoods, skilled demagogues often need to use only special emphasis by which an uncritical listener will be led to draw the desired conclusion themselves. Moreover, a demagogue may well believe his or her own arguments (for example, there are good reasons to assume that Adolf Hitler—certainly one of the most successful demagogues in history—sincerely believed his own anti-Jewish diatribes).
These impractical [political] schemes reflect at once Plato's discontent with the demagogy then prevalent in Athens and in his personal predilection for the aristocratic form of government
In the 19th Century, political reactionaries branded their opponents as demagogues and directed numerous reprisals and censorship against them. Representatives of the German Confederation of German-national and liberal groups were accused of Demagogenverfolgung, subversion, and sedition. After the July Revolution of 1830, the measures against the "demagogic machinations" were renewed, and especially, Fritz Reuter.
A famous usage was by the aging Erich Ludendorff, who was for a time a strong supporter of the early rise of Adolf Hitler and Nazi Germany. After learning of Hitler's appointment as Chancellor, he expressed his disappointment to German President Paul von Hindenburg: "By appointing Hitler Chancellor of the Reich, you have handed over our sacred German Fatherland to one of the greatest demagogues of all time. I prophesy to you this evil man will plunge our Reich into the abyss and will inflict immeasurable woe on our nation. Future generations will curse you in your grave for this action."
Hitler indeed would become regarded as perhaps the epitome of a demagogue, having successfully risen to power through appeals to the ethnic and nationalistic prejudices and vanities of the German people.