The style of music John Adams is known for, and which he composed for his opera Nixon in China, will be broadly familiar to anyone who's heard a Philip Glass film soundtrack (like Thin Blue Line or The Ice Storm): spare clusters of notes repeated, often across stately chord changes, to somewhat hypnotic effect. It's usually called "minimalism." But if Nixon, excerpts of which Adams conducted this past weekend at the PSO (where he is composer of the year), is a pretty rich work, it's due not only to the music, but also to the fascinating verse libretto, by poet Alice Goodman.

The Jan. 16 Heinz Hall show excerpted the 1985 opera's opening scene, with President Nixon and his wife, Pat, arriving for their historic visit, to be greeted by Premier Chou En-lai. The singers merely stood in a row, the orchestra behind them, and only baritone John Maddalena, with his long nose and hooded glower, looked much like the historical figure he played. (Mao was sung by tenor Russell Thomas, who's African-American, his wife, Chiang Chi'ing, by fair-skinned blonde soprano Hila Plitmann.) "News has a kind of mystery," goes Goodman's opening line for Nixon, and she and Adams proceed to flesh out a man who perceives himself as an actor on a world stage, his sense of majesty banal but his paranoia honed to a fine edge on the stone of his political pragmatism. Nixon, especially, repeats lines of verse, echoing Adams' arpeggios but also suggesting a certain disquietude; when he sings "my hand is steady as a rock," the orchestra bursts in discordantly on "rock," as if to mock him.

Pat Nixon, too, is given a good deal of depth: Goodman provides her with almost surreal visions of the America she and her husband are representing. ("The Prodigal. Give him his share: The eagle nailed to the barn door. Let him be quick. The sirens wail as bride and groom kiss through the veil," she sings in one scene.) But in Act III, performed here entire, President reduces First Lady to decoration: "There isn't much that I can do, is there?" sings soprano Jessica Rivera, when Dick tells Pat her lipstick is crooked. "Who's seen my handkerchief?"

Later in the act, the music gets more complex, more traditionally "orchestral," as the presidential couple recall their World War II experience, Pat stateside while Nixon did noncombat duty in the Pacific. Goodman also gives Dick some poetic lines -- "Picture a thousand coconuts like mandrill's head or native masks ..." -- but mostly, we're being shown these characters' limitations, how they're most comfortable in, hence trapped by, the past.

Adams, a trim, cheerful and silver-haired figure, introduced the work as "an opera for Republicans ... and Communists." He prefaced the performance (whose second half was his thrilling Doctor Atomic Symphony) with helpful commentary, so that we could more easily pick out the big-band-style saxophones that gave voice to a president's nostalgic memories of the days before the Cold War.