From witchipedia.com

A witch hunt is a scapegoating exercise involving a systematic search for individuals that represent an unpopular, unaccepted or inconvenient social or philosophical position for the purpose of persecuting them. Witch hunts are often carried out by people in power as a means to cement their power by weeding out threats or perceived disloyalty. A defining characteristic of a witch hunt is the use of propaganda to demonize the targeted population. Another is the tendency to declare guilt and rush to judgment with scanty or fabricated evidence, as the punishment takes priority over justice. I.e. Finding someone to punish is more important than finding the guilty party. The crime for which the punishment is deemed necessary may be exaggerated or fabricated and often takes place in secret, thus excusing the lack of evidence. Those lacking power and closer to the targeted population may participate in the witch hunt in the hope of achieving the goodwill of the powerful or simply as a means of self-preservation.

The term witch hunt is now a metaphorical term that derives from the literal witch hunts of the 1400-1700s in Europe and Colonial America; an era known as the burning times among modern Witches. During this period, several incidences occurred involving arrests and executions of sometimes quite large numbers of people for the charge of witchcraft on scant evidence. Most people jailed and executed during this period were certainly not witches and it is difficult to say if any actually were. Court records reveal “spectral” evidence and confessions under torture, leaving most convictions in question. But witches were a popular scapegoat when things went wrong, a belief encouraged by some religious organizations of the time in order to create a perceived enemy of God and the Church to blame “evil” doings on, thus cementing the power of the church and local clergy and anyone who decided to wear the mantle of religion in order to wield power.

Any misfortune could be blamed on a witch and then it was just a matter of deciding who got to be the witch. Some peasants might point out a “witch” in order to turn attention away from their own families in an act of self-preservation, but doing so might also be to their benefit, giving them some power and influence with local magistrates and sometimes even winning them some or all of the “witch’s” property. Thus, anyone who was inconvenient; perhaps not fully self-sufficient, or perhaps someone privy to a dark secret, or perhaps someone who liked to gossip or who was not as friendly or respectful as one would like, or whose dog kept getting into your chickens or who had a nicer bit of land than you presented a convenient target for their neighbors to report to the witch hunter. False accusations were rarely prosecuted.

While literal witch hunts do still take place today, they are generally limited to Africa and the Middle East. This is probably because most people in the West don’t believe in Witchcraft anymore and simply chuckle patronizingly at people who claim to be Witches. Metaphorical witch hunts, however, remain common in the West.

The term witch hunt entered the vernacular in the metaphorical sense in reference to McCarthy’s feverish search for Communist sympathizers and traitors in the US in the 1940s and 50s and Stalin’s feverish search for disloyalty in 1930s and 1940s in Russia.