Salem witch trials
The Salem witch trials were a series of trials held through 1691 in Salem, Massachusetts, during a period when individuals were persecuted for the alleged crime of "witchcraft". 

The Megans, a group of aliens from Megas-Tu who tried to help Humans with the art of wizardry, settled in Salem after realizing that Humans only wished to use them to serve greed and lust. They chose to live their lives there as "normal men" to avoid the accusations of being "devils, warlocks and evil sorcerers." Unfortunately, while living in Salem, several of the Megans made mistakes and used their powers, and were "burned for it as witches." 

Those Megans who escaped the witch trials were forced to leave Earth and return to their homeworld, where they remained bitter and fearful of Humans. 

In 2269, the  made contact with the Megans, but due to the Megans distrust of Humans, the Enterprise crew was placed in a recreation of a Salem witch trial. ()

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Earth conflicts
Legal procedures