IMAGINE rehearsing a new opera, days before its world premiere, even as the plot of that opera is being played out in real life and conveyed around the globe via CNN telecasts.Such was the case with the debut of "The Death of Klinghoffer" in Brussels this spring. As smart bombs assaulted Baghdad, tight security and tension surrounded the March 20th opening of an opera that takes a Palestinian hijacking, rooted in the Arab-Israeli conflict, as its starting point. Director Peter Sellars says that it was difficult "to watch the ground offensive start in the middle of rehearsal. It made one more aware of the need to treat this issue in a manner other than in the headlines." Concerns that the creative team of Mr. Sellars, John Adams, and Alice Goodman would ruthlessly exploit the 1985 murder of wheelchair-bound Leon Klinghoffer by terrorists aboard the Achille Lauro cruise ship, proved to be unfounded, according to press reports. Nor did the opera stir up anti-Jewish or anti-Arab protests on the streets of Brussels, as some predicted. There are no lurid scenes of Klinghoffer, an elderly Jewish tourist, being shot and thrown overboard. Instead, as American audiences will see tonight for the first time, the team has chosen to present a strictly "contemplative work," as Sellars describes it. "We don't show a sweet old man from New Jersey in his Bermuda shorts. There is no boat. The entire opera is conducted on quite a higher plane," Sellars explains in a phone interview. Rather than simply pitting victims against terrorists, or nation against nation, the opera uses the conflicts to make larger points about humanity. Composer Adams does this by interspersing the drama with large choruses, reminiscent of Greek tragedy and Bach's Passions. They serve as meditations on the meaning of life and death. "It's more of a spiritual piece. The overall effect is a very healing one," says baritone James Maddalena, who plays the role of the ship's captain. Though there are inflammatory moments, he says, the choruses "raise them to a transcendental level...." Nondescript costumes and role-switching help further to avoid sensationalizing the story. Contralto Stephanie Friedman, for instance, plays both a Jewish housewife from New Jersey and Omar, a teenage terrorist. Singers and dancers move about, not on a boat, but on George Tsypin's abstract jungle gym of tubular steel, cable, and gangplanks. The last act of Adams's previous opera, "Nixon in China," furnished the stylistic basis for "Klinghoffer," says Sellars. "By the last scene [of "Nixon"], it really had become a very lonely and sad series of mediations on the vanity of this world," rather than a representation of Nixon's historic trip to China. He hopes the new opera will "remind people that they're human, and how delicate human experience is."