Curiously, although reviews had given an impression that the play left matters of guilt up in the air, it seemed to me that Sister Aloysius did in fact catch a child molester--and that her doubts at the end were related to a Church heirarchy that appeared to protect and promote pedophiles. In the play, the accused priest, named Father Flynn (Chris McGarry), goes on to become pastor at another school--much as Mark Foley's priest appears to have been protected.
The conflict appeared to be more between Nuns (good) and Priests (bad). It reminded me of the Washington saying about John F. Kennedy--that the Republicans and Richard Nixon had support from bishops, while the sisters were all for Jack Kennedy. Another meaning for "sisterhood is powerful" I guess. It might be relevant, because the action of the play occurs shortly after the assassination of John F. Kennedy, America's first (and only) Catholic president.
There is another theme, of integration, which is handled in a complex manner. The victim approached by the priest is one of the first students to integrate the formerly all-white school for working class Irish and Italian kids. When Sister Aloysius invites his mother (Adriane Lenox) to discuss the situation, she begs the nun to keep the matter quiet. Interestingly, something similar seems to have actually happened in the Foley case. After that confrontation, Sister Aloysius becomes more determined than ever to "get" the priest.
She does--while keeping it quiet to protect the victim--and then, for the first time in the play, admits she has doubts. For Doubt is about doubt--including doubt about doubt itself...