VENICE -- This city's frail beauty is in itself a triumph over centuries of struggle with man and nature. It has outlasted plagues and killer tides, barbarian invaders, the whims of legions of politicians and, so far, tourists.

But the question now is: Can Venice survive a world's fair?

A growing number of prominent figures the world over are responding with a loud "no," a sentiment officially endorsed by the European Parliament in May.

They note that pollution and uncontrolled mass tourism are already shaking the delicate balance of the lagoon city. An influx of an estimated 30 million visitors almost 10 years from now for the planned four-month-long Expo 2000 would "kill Venice as we know it," according to a brochure published by the exposition's opponents.

Expo's supporters, led by Foreign Minister Gianni De Michelis, contend that only a world-class event will shake Italy's political establishment out of its habitual lethargy to confront Venice's very real problems. Investment and badly needed new infrastructure, he argues, would result. "Venice is already dying," he said recently. "We want to revive it."

Expo supporters have persuaded Prime Minister Giulio Andreotti to stand behind them, although even his coalition is divided on the issue. In a lukewarm defense of the idea before parliament on June 5, Andreotti suggested the Expo could be moved to the off-season -- an idea rendered difficult by the flooding and thick fogs that virtually shut down transport during winter.

But the real jury is still out: the Paris-based International Bureau of Exhibitions (BIE) must decide by Thursday among Venice, Toronto and Hanover, West Germany. With the deadline fast approaching, the European Community's environment commissioner, Italian Carlo Ripa di Meana, sounding "an appeal to reason," has urged Italy to drop its bid for Expo.

"The Italian government, while getting ready to assume the rotating presidency of the EC, can't ignore the European Parliament, whose majority opposes" Venice, he said.

Some 25,000 people have signed a petition against Expo, including designer Giorgio Armani, writers Gore Vidal and Umberto Eco, director Bernardo Bertolucci and Washington's National Gallery director, J. Carter Brown. On a recent day in Venice, only one of 20 randomly selected residents -- a man selling plastic souvenir gondolas -- came out in favor of Expo.

"No, un disastro," said Nedis Tramontin, one of the city's venerable gondola-makers, shaking his head in disgust. "They talk about all the investment it will bring, but we don't need more money. We get billions of lire from Rome, but politicians here don't know how to spend it. All they do is hold roundtables and working lunches. This city needs real ideas."

Said Renzo, a burly gondolier: "An Expo is something for terra firma." He gestured at the canals, teeming with motorized traffic, and at the water-buses, already jammed with passengers although still a month shy of high season. "We don't need any more visitors, thanks all the same."

What Venice really needs is residents, a species that is steadily declining. Expo foes argue that the event would drive up already steep rents and food prices, further inreasing the exodus. They also scoff at claims by Expo planners that the event's estimated 250,000 daily visitors would be spread evenly across the Veneto region, for which Expo events are also planned, saying few would miss the chance to visit here.

To hotelier Franco Tagliapietra, the whole issue boils down to toilets. He stood at the towering windows of the 14th century palazzo that houses La Residenza and recalled how on the last Saturday of Carnival festivities, the normally tranquil piazza outside was transformed into a noisy campground.

"They didn't have anywhere to go, so they relieved themselves in the side streets and canals," he said. "The stench was awful so we cleaned it all up ourselves. This city just doesn't have the facilities, the bathrooms, the drinking water, to handle those kinds of crowds."

It was a Pink Floyd concert last summer that shook many Venetians from their indifference and reveries. Some 200,000 fans camped out in Piazza San Marco, leaving behind garbage and human excrement that took the Italian army three days to clean.

The emotional tenor of the debate is one reason De Michelis, himself a Venetian, denounces attacks on Expo as "propaganda" and his critics as "Cassandras."

The consortium of businessmen promoting a Venice Expo, run by De Michelis's brother Cesare, says it would bring many benefits, lushly illustrated in a glossy book printed by the Foreign Ministry: state-of-the-art transport and telecommunications, an expanded airport and an ambiguous "ideas network" headquartered in the restored Arsenale, from whose shipyards the powerful Venetian republic's navy once set sail.

Venice is a city shaped by its water environment. Its dialect includes a special word for the reflection of water on a ceiling, and Wellington boots to wade through the winter's high tides are a part of every wardrobe.

Sylvia Franco, who runs an elegant clothing store, recognizes that some solution must be found for Venice's troubles but hopes the BIE will recognize "the limits we have living in a lagoon."