It's a warm Saturday night, and the party is getting hot at Mar-a-Lago, the Palm Beach estate that owner Donald Trump recently converted into a private club. As the Beach Boys harmonize on a makeshift stage, hundreds of revelers, many of them decked out in Hawaiian shirts, straw hats and leis, dance in the aisles and gyrate on wooden lawn chairs.

At the height of the fete, Mr. Trump asks the crowd: "Does this remind you of the Bath and Tennis Club, anybody?"

The answer is a definite no -- among the evening's partygoers, and for many more of the nearly 10,000 residents of this posh island town. But whether the contrast between the freewheeling Mar-a-Lago Club and the more-formal Bath and Tennis Club, as well as Palm Beach's other traditional social establishments, is good or bad depends on whom you ask.

Uptight and Offended

For Mr. Trump and his club set, Mar-a-Lago is a saving grace, affronting hypocrisy in a corseted culture of snobs. "Palm Beach is very much changing for the better," says the New York real-estate tycoon, "and a lot of that is because of Mar-a-Lago."

But for the old money that has long dominated this town -- mostly staid, conservative, publicity-shy philanthropists who donate tens of thousands of dollars at social functions each "season" -- Mar-a-Lago and its owner are the town's vulgar future made unpleasantly present.