It was a typically lazy summer night in Key West. A pack of the island's countless cats was padding in and out of the open doors of Captain Tony's, the oldest operating saloon in Florida, one of those places wallpapered with decades of business cards and expired driver's licenses. Bruce Springsteen's "Pink Cadillac" was up loud on the jukebox. Back in the shadows, past the long line of bar-stool loungers, pop star Jimmy Buffett had been talking with the saloon's owner, 69-year-old Capt. Tony Tarracino. Slamming his fist on the table, Tarracino stood up and shouted, "Goddam it. I'll fight these condo bastards if no one else will. I'm gonna run for mayor."

We've all heard Buffett sing of the Man ana Syndrome: strumming a guitar on a porch swing where the big worry of the moment -- in a world of worry -- is the whereabouts of a misplaced salt shaker. The song "Margaritaville" could well be a battle cry for the more than 1 million people who each year choose Key West as a vacation spot because, as they all seem to put it, "it's so laid-back." For the thousands of people who have made Key West their home, it's more of an anthem.

But on Nov. 5, Key Westers will be faced with precisely the sort of thing many of them came here to escape: politics -- and the decision to get out of their porch swings and out on the streets for a mayoral election that might well determine whether Key West's character will disappear along with its coastline.

Even Jimmy Buffett has changed his tune. He's acting as honorary campaign manager for the Captain, a Key West legend who inspired the title song on Buffett's new album, "Last Mango in Paris." The saloon owner, former gunrunner and member of two abortive Caribbean invasions, Tarracino must be the least likely mayoral candidate in the country, a man who just might be perfect for the job. Trouble in Paradise

Like most islands, Key West has always had the lure of paradise. Closer to Cuba than Miami, it is literally the end of the road: a four-hour drive southwest from Miami over 42 bridges, the longest of which spans a seven-mile stretch of ocean. It's the southernmost city in the country and, with an average annual temperature of 77 degrees, the only one that has never known frost. It's a place of startling vegetation and gingerbread houses and an organized nightly celebration of sunset; a place where life is simpler -- or should be.

Unfortunately, it is also real estate.

Key West has perhaps been luckier than most places, its slow pace of change due as much to its laid-back pace as to its isolation from the mainland. But in the past 10 years, high-rise condos and time-share resorts have sprouted all over the island, particularly, of course, along the shoreline.

Since 1980, no fewer than 23 major development projects have either been built or lie under development, 3,184 new units for an island 2 by 3 miles wide with a population the size of Georgetown's.

Though city planners talking of a growth rate of 2.5 percent per year, the real numbers are between 30 and 35 percent over four years.

Montana novelist Thomas McGuane, who comes back to the site of his "Ninety-Two in the Shade" at 8- to 10-month intervals, calls the changes "stroboscopic." "Sometimes," he says, "I wonder if I got off the wrong plane. The place looks more and more to me like a permanent job site, a development toilet." Pulitzer Prize-winning writer Philip Caputo, who lives there, inadvertently coined one of the campaign's slogans in a Tarracino endorsement: "Save, don't pave, our shoreline."

One city commissioner, George Halloran, fears and foresees "a whole new concrete playground; some sort of adult Disneyland." For the past two years he has fought an unsuccessful battle for nothing more than a six-month moratorium on new permits so that the city could try to assess the impact of these massive developments on such essential matters as traffic, water (which arrives by pipeline through 90 miles of Florida Keys), sewage (now pumped untreated into the ocean) and electricity from a city plant that delivers blackouts almost monthly.

There's also a lot of talk about corruption. Earlier this year, a rash of federal racketeering and drug-smuggling indictments resulted in quite a few long jail terms, including one for the city's assistant police chief and three veteran detectives. A second wave of such indictments is imminent. There's research under way to try to determine cause of one of the highest rates of multiple sclerosis in the nation. And, as is true all over, the gay community tries to keep the lid on the threat of AIDS panic. The Conch Republic

Home to Tennessee Williams, Hemingway and Audubon, Key West is one of our country's geographical legends, one of the last holdouts of the free spirit. The prevailing attitude is live-and-let-live. One can find knife-toting shrimpers, Pulitzer Prize-winning writers, sailors on leave, cruise ship vacationers, and members of the gay community all sipping margaritas on adjacent bar stools at establishments like the Full Moon Saloon, Havana Docks, and Hemingway's favorite haunt, Sloppy Joe's. Three years ago, in response to Border Patrol drug-search roadblocks in and out of town, Key West threatened to secede from the Union. "Conch Republic Week" is still celebrated in April. (Locals, even the high school football team, are known as Conchs -- pronounced Konks -- after the conch shell.)

Key West's political representation -- quite democratically -- is as offbeat as its population. Until last month, one of the city commissioners was also responsible for providing the astrological column for the town's monthly newspaper, Solares Hill. Another is a former pizza shop operator who, lately, has found employment as a carpenter at the local treasure salvage operation. Another is an admittedly prodevelopment plumbing contractor who is famous for his grasp of both the issues and the English language. At a recent City Commission meeting, he responded to another commissioner's proposal that only domestic pipe be used in a sewage project by vehemently saying, "We don't want no domestic pipe bein' used. Only pipe made in the U.S. of A."

The reigning member of the City Commission has been Mayor Richard Heyman, an educated, well-respected homosexual art gallery owner who recently suffered a painful bout with shingles and decided not to run for reelection.

As quick as the tiny lizards that leap about town, three candidates announced their intentions: Steve McDaniel, a man who makes "no bones about being prodevelopment," and heads up the agency responsible for protecting the city's interests in the planned development of a 110-acre tract of waterfront the city's buying from the Navy. Last week, the city's attorney acknowledged that no one in city hall had yet even seen a copy of the developer's 99-year lease, which includes plans for an additional 200-unit hotel with restaurant and convention facilities, and a marina, as well as up to another 800 condominium units.

*A bank vice president and city Port Authority director with the unlikely name of Tom Sawyer whose campaign ads thus far have been his re'sume'. He was once Jaycee of the year.

*Bob Garcia, a real-estate salesman of Cuban descent whose campaign slogan has been "Let's Keep Key West Nice." "Forget the Issues"

While the local cocktail party chatter focused on who else might run, Capt. Tony got his saloon's new tax bill in the mail. In one year, it had jumped more than 200 percent. That was the last straw.

"You know," he says, "for centuries this place has been a haven for pirates. Nothing's changed except that now they wear vests and ties and their necks are crooked from being in cities too long. They're always looking up, nervous when they see the sky instead of concrete."

Within days, there were fundraisers, not at the hotels and conference rooms, but at local shops like Bob's Flowers and Balloons, at gay guest houses like Big Ruby's and at beach-front homes. Even competitors' bars have thrown parties, where Tarracino reminds the crowds, "You know what's really great about America? For every one of them, there's 300 of us. Let's kick their asses."

Thomas Sanchez, whose epic Key West novel "Mile Zero" will be published next year by Simon and Schuster, sees Tarracino as being "in the grand tradition of American politics, like Will Rogers -- who was mayor of Beverly Hills."

Can a bar owner make a good mayor? "If you can run a bar in Key West," says Sanchez, "you can run anything, from guns to countries. I've said many times that Key West is Dodge City on the Gulf Stream. It's about time it had its philosopher-marshal to make Key West safe from Middle America."

In a humorous radio ad that Buffett flew up from a recording studio in St. Thomas, the singer suggests voters "forget the issues . . . Let's just remember why we came to Key West in the first place."

"He's right," says Tony, standing on the sidewalk outside his saloon. "There are lots of issues but, as far as the people are concerned, this election is about what's happening to this island and what's going to be left -- for our kids, and their kids.

Someone is passing along the street. Tarracino excuses himself, turns away and calls out "J.T., have you registered to vote yet, you turkey?"

"You better believe it, Captain!" comes the answer, with a fisted high sign.

At the next street corner, in Sloppy Joe's, a 350-pound-plus, shaved-headed bouncer named Tiny puts his hand on my shoulder and lifts me aside. "You the writer?" he asks.

"Why?"

"A few years ago I got real sick and the Captain loaned me money to pay my rent until I got back on my feet. He used to call to check in on me, too." Then he shakes a huge finger in my face and says, "Tell them anybody who votes for one of these blueprinters instead of for him is either stupid or in trouble -- with me."

At the sight of my note pad, he flashes the kindest smile I've ever seen on a bouncer. "Nah," he says, with a shrug off his door-wide shoulders. "Just tell them if they don't, I'll kill them."