Demagogue
A political leader who amasses power by exploiting popular prejudices, fears, and emotions rather than by reasoned argument or appeals to evidence. Demagogues characteristically construct an enemy — often an out-group already disfavored by their base — and present themselves as the unique protector against that enemy. The term originated in ancient Athens and was used pejoratively by Plato and Aristotle to describe leaders who manipulated the demos (the people) against their own long-term interests.