“Doubt: A Parable,” John Patrick Shanley’s Pulitzer Prize-winning play now on stage at Nyack’s cozy Elmwood Playhouse, is a turf war in what might seem the unlikeliest of places.

It pits Sister Aloysius, the principal at the fictional St. Nicholas School in the Bronx in 1964, against the young Father Flynn, a newcomer to St. Nicholas.

She has the school; he has the pulpit. She has the classrooms; he has the rectory, into which nuns are not permitted.
She follows the old ways, the old rules, the certainty of routine and long-held traditions.

He embodies Vatican II, a kinder, gentler church, one that might allow the singing of “Frosty the Snowman” at a Christmas pageant.

She is fountain pen. He is ballpoint.

He is the future.

She has her doubts.

It’s riveting and thought-provoking stuff, as played out on the tiny Elmwood stage by director Michael Edan’s top-notch cast of four.

(Shanley directed the film version of the story, starring Meryl Streep and Philip Seymour Hoffman.)

As Father Flynn, the idealistic young priest, Jonathan Peck is charming and likeable, whether in the pulpit or when teaching basketball to unseen boys. Who wouldn’t be charmed by a priest who can  speak about faith while mimicking an old Irish priest?

Well, Sister Aloysius, for one, played masterfully by Robin Peck in a performance that is controlled and efficient as Jonathan Peck’s performance is natural and earnest.

The Pecks are not related.

“Don’t be charmed by cleverness,” she warns the young nun, Sister James, (a fluttery, ever-on-the-edge-of-tears Annemarie MacSweeney), who finds herself in the principal’s office.

Sister Aloysius takes the opportunity to share her educational manifesto with the young teacher. Her old-school style doesn’t have room for silly endeavors like art and dance.

“Be a fierce moral guardian,” she warns. “Study others and you will not be fooled.”

Aloysius convinces Sister James to put up her guard, to view others with suspicion. A child’s nosebleed, the elder nun suggests, might just be a ploy to get out of class.

“My job is to outshine the fox in cleverness,” Aloysius says.

And she has serious doubts about this young priest, doubts she’s willing to share with young Sister James and, eventually, with Father Flynn himself, in a scene that crackles with excellent dialogue expertly delivered.

Edan directs briskly, beginning the action with whispers whirling around the theater. After all, isn’t that how all doubt begins?

He opens with a slick and effective video montage of images from the 1960s — created by set designer Andrew Barrett — to set the scene and bring us to St. Nicholas. It serves the moment well, but one wonders if we really needed to see a photo from President Kennedy’s autopsy to get us to 1964.

Act 2 begins with another video that blurs the time frame, with images of the King and RFK assassinations, four years removed from the action of the play. There are also plenty of photos from Vietnam and from the women’s and civil-rights movements, set to Jimi Hendrix’s cover of Dylan’s “All Along the Watchtower,” recorded well after 1964.

Edan’s point, one supposes, is that the tumult of the age led to doubt in all spheres of life.

It’s a point worth making and the videos are well produced, but they seem overlong and jarring when they bookend the simple, clear and understated action of Shanley’s play.

For a play that is about what’s not said but wondered about, the videos seem to be too certain, too graphic. But perhaps that’s Edan’s goal. If so, mission accomplished.

On the stage, he crafts moments carefully, drawing on the always strong production team at the Elmwood to paint memorable stage pictures.

Barrett’s excellent set has the principal’s office and a courtyard sharing the stage deck and the pulpit and altar high above the action.

The 99-seat Elmwood is so intimate that at a preview performance one could hear the stage manager calling sound and lighting cues from the booth. It’s doubtful that those are the kinds of whispers Edan had in mind.

There can be no doubt that this battle of wills has victims and pawns.

Tracey McAllister does a fine job as the mother of the school’s first black student who is summoned by Sister Aloysius. Their meeting reveals a woman who is trying to get by, who sees the hand she’s dealt and plays it.

She chooses not to entertain doubts, even if that means her son may be a victim, too.

And “may” is key.

Shanley — and Edan and his team at Elmwood — leave it for the audience to decide whether Sister Aloysius’ doubts are well-founded or not.

(Shanley famously printed his e-mail address in the Playbill and invited comments, questions and conclusions.)

As with any parable, lessons are learned here, although what those lessons are may differ from one audience member to the next.

And that doubt, that difference of opinion, is what makes a little theater on Park Street in Nyack an excellent place to be on a cold wintry night.

Don’t doubt that.

“Doubt: A Parable”
Where: Elmwood Playhouse, 10 Park St., Nyack.
When: Weekends through Feb. 7, with curtains at 8 p.m. on Fridays and Saturdays (and Thursdays, Jan. 29 and Feb. 5) and at 2 p.m. on Sundays.
Tickets: $21, $18 for students and seniors. No discounts on Saturdays.
Call: 845-353-1313
Web: elmwoodplayhouse.com
With: Jonathan Peck, Robin Peck, Annemarie MacSweeney, Tracey McAllister. Directed by Michael Edan

Photo by Rob Woudenberg: Jonathan Peck as Father Flynn tries to convince Robin Peck as Sister Aloysius to see things his way in “Doubt: A Parable” at Nyack’s Elmwood Playhouse.

“Doubt,” elsewhere
M&M Productions Acting Company, Inc., is also presenting “Doubt.”
Jan. 17 at 2 p.m. at the Irvington Public Library, 12 S. Astor St., Irvington
Jan. 18 at 2 p.m. at the Mt. Pleasant Public Library, 350 Bedford Road, Pleasantville.
Performances are free.
With: Michael Muldoon, Janice Fay Hanges, Leslie Smithey and Sarah Smegal. Directed by Stewart Hanges.
Web: www.MMPACI.com