ANSWER:
The word demagogue, meaning a leader of the common people,[1] first arose in ancient Greece, originally with no negative connotation,[2] but eventually came to mean a troublesome kind of leader who occasionally arose in Athenian democracy. Even though democracy gave power to the common people, elections still tended to favor the aristocratic class, which favored deliberation and decorum. Demagogues were a new kind of leader who emerged from the lower classes. Demagogues relentlessly advocated action, usually violent[3]—immediately and without deliberation. Demagogues appealed directly to the emotions of the poor and uninformed, pursuing power, telling lies to stir up hysteria, exploiting crises to intensify popular support for their calls to immediate action and increased authority, and accusing moderate opponents of weakness or disloyalty to the nation. All politicians in a democracy must make occasional small sacrifices of truth, subtlety, long-term concerns, or other matters that don't have immediate popular impact or else they will lose the popular support which is the base of their political power.[4] Demagogues do these things relentlessly and without self-restraint.[4]
Demagogues have been found in democracies from Athens to the present day.[3] Democracies are instituted to ensure freedom for all and popular control over government authority; through their popular appeal, demagogues exploit the freedom secured under democracy to gain a level of power for themselves that overrides the rule of law, thereby undermining democracy.[5] The Greek historian Polybius thought that democracies are inevitably undone by demagogues. He said that every democracy eventually decays into "a government of violence and the strong hand," leading to "tumultuous assemblies, massacres, banishments."[5]
Throughout its history, the word demagogue has been used to disparage any leader thought to be manipulative, pernicious, or bigoted.[3]
http://en.wikipedia.org/wiki/Demagogue
