In The Crucible by Arthur Miller, what kept the morals of Salem from spoiling?

I think the morals in Salem did spoil. Guilt, anger,
revenge, and lies stunk up the whole place.

If you are
wondering why the Rebecca Nurse and John Proctor type characters were able to keep their
moral compasses in check, then I think you could argue that these two were people who
believed in their God and had agreed to live according to the disciplines of the bible.
They both made conscious choices to live according to telling the truth, and they
suffered the greatest price for it unfortunately.

This is
why The Crucible is such an important piece though. It demonstrates
that a society can go overboard with the effort to live according to rules and it is
important to consider the truth and how people really treat each
other.