Make an opera about contemporary topics, the conventional wisdom goes, and you’ll draw in a new audience that doesn’t think it likes opera. Thus, we have Jake Heggie’s “Dead Man Walking,” based on the book and movie of the same name, which came to the Washington National Opera for the first time Saturday night, the latest of some 50 productions for this most successful of contemporary American operas.

I’m not sure, though, that “Dead Man Walking,” the opera, is calculated to draw in new audiences as much as it is to please people already familiar with opera. Yes, it’s based on the true story of a murderer on death row and a nun’s fight to save his life, but it’s steeped in operatic tradition. Heggie’s romantic score is full of fleeting references small and large to bygone works, from the threatening male chorus (the mob in “Peter Grimes”) to the rapid violin figures expressing a character’s consternation (Violetta’s distraught entrance in Act III of “La Traviata”). It also involves arias, ensembles, melodies and heightened emotion — all familiar tools in the operatic arsenal. And Terrence McNally’s libretto even has a good dose of cliche, which Francesca Zambello’s production amplifies, down to the crucifixion pose of the doomed man at the end.

All these things are just fine — and can be, indeed, a good thing in a new opera. What the piece lacks, though, is subtlety — not a conventionally operatic trait but something that new audiences might appreciate, particularly when it comes to difficult material. The original book revolves around the question of whether the death penalty is justified even in cases of reprehensible violent crime. Yet despite the truism that music, in opera, conveys nuances of emotion that go beyond words, this opera hammers everything securely home with big, can’t-miss-’em melodies and themes in the score; a lack of ambiguity in the words; and even an undermining of dramatic tension by graphically enacting the double murder at the outset, so there is no question about the guilt of the convict Joseph De Rocher, only about whether he will admit it.

The result is a piece that feels as if it is encased in quotation marks, saying, “I am an opera!” but not quite, to me, transcending the formulaic. It certainly has some tear-jerking scenes, particularly those involving the convict’s mother, Mrs. De Rocher, whose jailhouse farewell to her son was made all the more touching on Saturday night by the remarkable mezzo-soprano Susan Graham singing a part that everyone in the audience probably wished were twice as long to better showcase her. (Graham sang the lead role of the nun, Sister Helen Prejean, in the world premiere in 2000.)

The rest of the cast couldn’t quite match her, although Michael Mayes, in his WNO debut, did a strong job embodying Joseph in an intense, tortured and laudably dramatic performance.

It didn't help that, while Heggie's vocal writing is touted as being singer-friendly, it didn't set anyone off to a very flattering advantage. Jacqueline Echols, the dynamic Domingo-Cafritz alumna who sang Sister Rose, has plenty of high notes but settled into her wonted warm vocal territory only after she got past the loud stratosphere of her first scene (in which the nuns happily teach music to dancing children, providing emotional relief after the stark murder scene but interfering with the plot development — a new audience might be left wondering what is actually going on).

Smaller character parts were adequately cast, including the quartet of parents who lost their teenage children, played by Wayne Tigges, Kerriann Otaño, Robert Baker and Daryl Freedman, a current member of the Domingo-Cafritz program, as is Timothy J. Bruno, who was sympathetic as the Warden.

The marquee role of Sister Helen went to Kate Lindsey, who has been stunning in other performances I've heard, but for all the acting chops she has displayed elsewhere, she couldn't quite bring this character fully to life. Her voice sounded thin, vying with the pumped-up orchestra under Michael Christie's vigorous baton, and her character, initially quirky, became largely two-dimensional. This is perhaps because the piece gives her little to do beyond pursue her obsession, first to free Joseph and then to get him to confess his crime.

And after Sister Helen does extract the 11th-hour confession, what then? Is Joseph forgiven? Shriven? Has he, indeed, died for our sins, in Zambello’s crucifixion-like final tableau, rather than his own? It’s a case of cliches run wild but not thought through. I’m not sure this is the message the opera really wants to be giving, and Zambello’s routine, uninspired production did little to bring any greater depth for the audience.

If you already like opera, you may well like the attractive music and find much in this piece you recognize. If you’re new to opera and its conventions, you may find the work simply long and clunky. “For this kind of straight-ahead movie to work, the acting must be strong without even a breath of theatricality,” the Los Angeles Times critic Kenneth Turan wrote about the original film. The operatic version of “Dead Man Walking,” and this production, tested that statement by attempting the inverse and, unfortunately, proved it right.

“Dead Man Walking” continues at the Kennedy Center through March 11.