How is the setting of Arthur Miller's The Crucible essential to the theme and conflict of the story?

The historical setting of The Crucible is 1692 in Salem, Massachusetts. As a Puritan community, God and religion were the center of people's lives, as well as the center of the government in Salem. The Puritans had a strict sense of what it meant to be a Christian and to behave in a godly way, setting up an automatic man vs. society conflict, as not every member of the community necessarily agreed with the prescribed behavioral expectations (consider John Proctor's stubborn personality, and even Elizabeth Proctor's choice to lie to protect her husband). 

Additionally, the Puritans had a sense that the Devil and evil were very present and active in everyday life, which is why they are so ready to get carried away looking for witchcraft. This allows the man vs. society conflict to escalate and grow. Abigail and her friends rebel against society by dancing in the woods, then turn and position other members of the community against society by claiming they are witches, deflecting the attention from the girls' own "sins." Presumably, in a less restrictive society, the girls would not need such distractions from their dull lives and, even if they did go off and dance naked in the woods, it wouldn't be such a big deal. 

Because the government of Salem is controlled by human men who claim to be representatives of God, plenty of man vs man conflict arises as people debate what is correct and as Thomas Putnam takes advantage of the situation to get revenge on his enemies. The supposed infallibility of those in charge is both a theme and a way for this man vs man conflict to escalate as Putnam pushes those in power, like Reverend Parris, to act in ways that bully and implicate his enemies. 

This setting was also chosen very deliberately by Arthur Miller, who saw the search for Communists in Hollywood by the House of Un-American Activities Committee and Senator Joseph McCarthy as a modern day witch-hunt, with people's fears of Communism and the Soviet Union causing them to rally, mob-like, behind a senator with excessive power and influence and to implicate people unfairly. By using such a well-known historical event of mass hysteria, Miller is critiquing the simplification of the world into good vs evil (one theme), as well as the importance of reputation in a society that lives in fear (another theme), ideas that are prevalent in both the play and the history of McCarthyism.