In the role of Father Merrin, the old priest who oversees the exorcism, Chamberlain also serves as the story's narrator, a superfluous assignment in a play where themes are underlined with a bloody red Sharpie. It's a credit to Chamberlain's abilities that these frequent asides aren't more tedious. Pielmeier gives Merrin remarks that seem like desperate stabs at relevance. Chamberlain's character begins the play with a short monologue: "For anyone who doubts the existence of the devil as I once did, I have three words. Auschwitz. Cambodia. Somalia." We get it: evil still exists in the world.
It must be noted that the suave gravity of Richard Chamberlain as Father Merrin, redolent of the patrician Catholicism of William F. Buckley, greatly elevates the proceedings whenever he is stage center. One wishes he could have been as witty.
The cast is wonderfully and intensely focused throughout especially Shields as the despairing mother Chris, Harry Groener as the drunken director Uncle Burke Dennings, Roslyn Ruff, so caring in her spurt-like appearances, and Emily Yetter, amazing in the physical demands of the role of Regan. David Wilson Barnes as Damien Karras and particularly Richard Chamberlain as Father Merrin are exceedingly in control by the very nature of the men they are playing. Barnes has moments of guilt and emotional release that he is allowed to play out in the script, but Chamberlain, also acting as narrator, plays with the utmost grace and intelligence but with far less passion. I don't believe it to be an actor choice, but it's built-in, and does at least add a dimension of doubt/uncertainty to the whole question of God/Devil, Love/Pride at hand.
Chamberlain fares even worse, sauntering in periodically to describe encounters with evil informed by Blatty's occult research (for readers of the novel, those are the pages you flipped past en route to the next outrageous set piece). His bland, amiable manner is so reminiscent of the narrator in "The Rocky Horror Picture Show," you expect to learn combatting Beelzebub involves just a jump to the left and then a step to the right.
Chamberlain is saddled with the worst of it. His character is the exorcist, but he also serves as the play's pontificator, routinely interrupting the story to deliver a mini homily on its meaning. Fortunately, the veteran actor is a smooth operator, and for the most part his velvety voice undercuts the strained theological navel-gazing that Pielmeier, author of "Agnes of God," can't get enough of. But there's little that can be done when, after Regan has just chewed off a piece of one of her doctor's ears, Chamberlain is compelled to deliver the following footnote: "This is a struggle between good and evil — for heaven's sakes, even if you don't believe in the devil you can embrace a metaphor, can't you?"