For operas not commissioned by an established opera company, the road to performance is a rocky one – if it leads anywhere at all.

Tom Cipullo’s “Glory Denied” still awaits a full staging, but it has fared better than most, in part because of Mr. Cipullo’s high standing as a song composer. In 2004, the opera’s first act received a read-through in City Opera’s prestigious Vox series. And on Monday evening, the full opera, presented by the Center for Contemporary Opera in a “staged reading” with piano accompaniment, attracted an overflow audience to the Thalia Theater at Symphony Space.

“Glory Denied” is based on Tom Philpott’s oral-history book of the same title. It recounts the sad fate of Colonel Jim Thompson, America’s longest-held prisoner of war,who languished for nine years in North Vietnamese custody. Sustained during the ordeal by his devotion to his wife and family,he returned home to find that his wife had taken up with another man. Efforts at a reconciliation proved to be futile, and Thompson died in 2002 an embittered man.

As Mr. Cipullo explains it, he read a review of Mr. Philpott’s book in 2001 and immediately recognized the story’s potential for opera. The result is not a conventional narrative opera: It calls for only four singers, who collectively portray only two characters, Thompson and his wife, Alyce.

Mr. Cipullo has adopted the trendy device of having different singers play young and old sides of the same character. Young Alyce roughly corresponds to the idyllic woman who exists in Thompson’s memory, while the older Alyce is the woman his wife actually became. The device works less well in the case of Thompson himself, for his tragedy might have been more powerful if concentrated in a single performer. (It should be noted that Osvaldo Golijov’s opera “Ainadamar” gained in lucidity when, in its revised version, the “young” version of the actress at the heart of the story became her student instead.)

The characters also double as other people: The older Thompson, for example, becomes a prison guard, who chillingly tells young Thompson that there are still Frenchmen imprisoned because they are unfit to return to their families. And young Alyce, who generally has an angelic demeanor as she sings of humdrum events back home, sometimes echoes sentiments of her hard-edged counterpart. Still, the opera wasn’t too hard to follow, and the intelligibility of the words in the small theater was of no small assistance.

In the early stages of “Glory Denied,” Mr. Cipullo can’t avoid touches of that grayish, all-purpose music we hear so much of in new American opera. But the largely expositional Act I culminates in an impassioned quartet, which derives some of its power from seemingly random sentiments expressed by the singers. Mr. Cipullo’s neo-Romantic style blossoms in Act II, when Copland-like suggestions of Americana accompany Thompson’s homecoming.

Having culled his libretto from the book, the composer allows himself only one freely creative moment, a “catalogue aria” for the older Thompson about changes to society wrought by the turbulent 1960s. This is one of the opera’s best pieces, with lines like “pillpopping, one-stop shopping, polyester, wife-swapping.” It lightens the mood but its sarcasm keeps Thompson in character.

Later, to a bristling accompaniment, the older Alyce catalogues the hardships she has endured, such as phone calls in the middle of the night from anonymous war protesters. Older Thompson also has a moving scene that doesn’t descend into sentimentality when he addresses his church congregation. In the final scene, to an insistent, agitated accompaniment, he resolves to face life as he did as a prisoner: one day at a time.

Music director Mark Shapiro presided over a fine cast. Soprano Jody Sheinbaum sang with pure tone and an engagingly innocent manner as young Alyce. Lucy Yates, also in fine soprano voice,was assertive as older Alyce without making her into a total shrew.

The two Thompsons are both high baritones. Richard Byrne sang young Thompson’s high notes with the assurance of a tenor, but through no fault of his own he was largely redundant dramatically in Act II. Chris Pedro Trakas responded affectingly to the demands of the older Thompson’s role. And the excellent pianist Jeanne Golan made a fine moment of the expressive interlude before the final scene.

Charles Maryan’s staging rather pointlessly kept the other singers onstage for the final scene, variously approaching and receding from the older Thompson. Otherwise, Mr. Maryan’s work, and that of the lighting designer, Dana Hunter, was strong. Indeed, because of the nature of the work, it’s hard to know what it would gain from a more elaborate production, although there would be room for deepening individual performances.