''Evil days lie ahead," wails the traumatised chorus. Rallied by a demagogue, the crowd cheers itself up in an outburst of belli- gerence: "Daring to die, we must defend our nation."
The lines come from English National Opera's The Capture of Troy, which inaugurates a two-part production of Berlioz's The Trojans, but they could be quotations from recent tabloids. Classics exist in a perpetual present, and the opera Berlioz derived from Virgil's Aeneid has never seemed more pertinent. When Troy is torched, Aeneas sails off to found a new global empire in Italy. If Rome is the new Troy, as the prophetess Cassandra declares, then America is a newer, brasher Rome. Dido, who kills herself when Aeneas quits Carthage, has her own moment of prophetic foresight, and describes the fall of another civilisation. Richard Jones's production reaches that final scene in May, and it is easy to imagine the identity of his vengeful Hannibal.
The contemporary parallels are starkly inked in by the designer Stewart Laing. Troy is besieged Manhattan, with a toppled flagpole, ignited skyscrapers, and fragments of an aircraft hulk still smoking. This is a culture that has failed because of its shoddy falsity. At Hector's funeral, the television audience is treated to a maudlin, deceptive sermon on family values, with home movies of JFK cuddling Jackie and romping in the Oval Office with their son. The sacred objects uncrated by priests to propitiate the gods are goofy statuettes that Jeff Koons might have designed, and the snout of the wooden horse that contains the invading army twists in a Disneyesque smirk. The mass suicide of the Trojan women - incited by the berserk, twitching Cassandra of Susan Bickley - discloses the underlying self-destructiveness in all this glutted surfeit. One of the imperilled virgins makes frantic love to a phallic missile, while her hyped-up sisters, elated by the apocalypse, strum electric guitars not lyres.
There is no salving hero to rely on: the Aeneas of John Daszak is a flabby functionary in a business suit. No wonder that the conducting of Paul Daniel, febrile and convulsive, suggests a collective nervous breakdown. What is missing so far - and it may be supplied in The Trojans at Carthage, when Jones will work with a different designer - is any sense of the amplitude and grandiloquence, combining Virgilian pomp with an unruly Shakespearean vitality, to which Berlioz aspired. The epic dwindles to a cartoon.
Though Jones may equate doomed Troy with New York, in New York itself there's a different, more bravely resilient view of the wounded, threatened, jittery city. The Metropolitan Opera's new production of Les Troyens avoids any opportunistic references to current qualms. The epic, in this case, is not a Whitmanesque monologue but a song of ourselves, a concerted tribute - like that paid by Dido during the festivities at the Carthaginian court - to warriors and poets, builders and navigators, and even to the farmers who feed us.
The sound that James Levine entices from his superb orchestra is effervescently nervous in Troy, lush and lavish in Carthage. Within a single set designed by Maria Bj0rnson, the director Francesca Zambello neatly differentiates the two settings. Battle-scarred Troy huddles inside a scaffolding of shards and jagged sticks; pastoral Carthage basks in idyllic sunlight. Cassandra, predicting catastrophe, is a ravaged harpy, whereas the matriarchal Dido presides over a socialist utopia, glad-handing admirers and pondering models for a new and ideal city. As usual, Zambello adds her own feminist gloss. Both women are sidelined by male aggression and ambition.
Cassandra cannot disengage her lover Chorebus from the fray, and Dido (likened by Zambello to Indira Gandhi and Hillary Clinton) falls victim to the pious political crusade of Aeneas. As Troy burns, and when Carthage collapses, the vacant sky is suddenly filled by a view of the carved dome of the Pantheon in Rome - which could also, come to think of it, be the Capitol in Washington, DC.
Emotionally, the emphasis in both places is on cohesion and moral support. When a panicking Aeneas delivers the news of Laocoon's death, the soldiers rush to clutch him and the women hug each other for solace. In Carthage, Dido and Aeneas sing their enraptured erotic duet while wandering through a moonlit park crowded with paired lovers lazily tussling on the ground.
As Cassandra, Deborah Voigt hurls herself around gamely enough, even though she sounds squally not scalding. Lorraine Hunt Lieberson's Dido is magnificent: beaming with civic pride, she radiates an affection made audible in the generosity of her singing, and her surrender to solitary grief is unbearably touching. Virgil announced at the start of his poem that his subject would be "arms and the man". Berlioz, to his credit, is more interested in love and the women.
Aeneas is the indispensable Ben Heppner. After months of drastic dieting, he now has a physique to match his burnished, mettlesome voice, and he reveals himself as an agile, responsive actor. When Aeneas passes on the heroic vocation to his son, he soars up to an exposed vocal pinnacle on the word gloire. In the opera, such high notes as these replace the deeds that the epic character performs on the battlefield. They are demonstrations of valour, and they compel us to revise our view of human possibility. Les Troyens, when presented as finely as it is at the Met, has the same ennobling value: it is a monument to the idea of accomplishment, and to the ambition that produces empires and such imperial by-products as pantheons, cathedrals and opera houses.
The Trojans at Carthage opens at the London Coliseum, London WC2 (020 7632 8300 or www.eno.org) on 8 May. Ben Heppner appears in Les Troyens, with Colin Davis and the London Symphony Orchestra, at this summer's BBC Proms