Sardi's in its heyday, they dream, or the Moulin Rouge of Paris. Maybe even one of the elegant French salons that so bewitched Marcel Proust, or the Round Table at the Algonguin. A place, they muse, where artists, politicians, thinkers and stars can meet in dimly lit delight.

These are ambitious hopes for Washington 1979, a town and a time that don't have enough European literati or American millionaires to fill private clubrooms night after night. Nonetheless, the four investors in a new private room called the Polo Club, which opened with a lot of glitz and fanfare at the Sheraton-Carlton last night, still dream.

But the scene from the Sheraton-Carlton was anything but intimate. Instead, hundreds and hundreds of people -- a few congressmen, a few socialites, a lot of car dealers, suburb- anites, real-estate agents, fashion models, media people, retailers and even polo players -- mobbed the lobby and stairs leading down to the Polo Club. Some were forced to wait in line outside for more than an hour after the District of Columbia fire marshal, who is himself a member, decreed the lobby crowd unsafe.

Policemen stationed at the door got involved in several skirmishes with angry patrons.

"They've got to be kidding," said Jack Whittemore, a polo player. "I mean, this is supposed to be the most elite club in town and everybody is standing out here in line."

"If you'd brought your crop and boots, they might have let you in," said polo fan Lilibet Clarke, who was waiting herself.

"This is like Studio 54," complained another guest.

A few congressmen, like Sen. Lloyd Bentsen (D-Texas), waited briefly in line, then left. But Rep. Tom Railsback (R-Ill.), who is not a member, stuck it out for 45 minutes and was finally let in the door. "I was kind of intrigued by the fact that there was such a long wait," he said.

Alan Weitzman, one of the Polo Club investors, greeted the long line of guests at the door, guests who included Rep. Barry Goldwater Jr. (R-Calif.), Effi Barry, socialites Tandy Dickinson and C. Wyatt Dickerson, and fashion designers Zandra Rhodes and Oleg Cassini. "I'd love this room to be a great room -- a page in Washington history," Weitzman said.

And Tommy Curtis, another investor and local bar business vet who wears the initials "T.C." on his sunglasses, has said he hopes the Polo Club will create "a new social order." He sees in the young professionals of increasingly cosmopolitan Washington "people who are successful at 35, but who aren't names. Yet they're going to be names."

But for all the eloquent buildup, the Polo Club still has drawn a good deal of scorn in this town. Traditional socialities say any club that invites 4,000 to become members and then accepts 1,000 is hardly exclusive and certainly not the old Algonquin.

Still, those who paid from $100 to $350 to join did include Sens. Ted Stevens (R-Alaska), Lowell Weicker (R-Conn.) S. I. Hayakawa (R-Calif.), Reps. Lindy Boggs (D-La.) and Charles Wilson (D-Tex.), developer Marshall Coyne, surgeon William Funderburk, White House staffer Jo Carpenter and Bill and Taffy Danoff of the Starland Vocal Band.

"What these sorts of clubs do," says a socialite who was a founding member of the private nightclub Pisces, "is attract a lot of attention for about two months, and then after that all you see is a lot of dentists from Rockville.

"I've been in this town for a long time," he continues, "and I've never seen these things work. This is not a town for private clubs, and it never has been. It's mostly a town for at-home entertaining. This isn't Manhattan, this is Washington."

But if you listen to the four investors (including Weitzman, the public-relations maverick; Curtis, former deejay; Lee Nathanson of Leasing Systems Inc.,; and Jack Boyle of Cellar Door Concerts, Washington, not Manhattan, is exactly the point.

"There's a social evolution going on in this town," says Nathanson, the money manager of the four. He offers this evolutionary theory:

"For many years here, the social world located around the worthy causes and you'd have benefits for everything. Then you had the era of the great hostesses, Perle Mesta and everything, and that was sort of restrictive. Then there was a period in Washington when people didn't go anywhere unless it was for a political fund-raiser. And then, all of a sudden, the singles bar was born and that sort of polarized people.

"Now," he concludes, "Washington is ready for a club like this that will eliminate the excuses and the need for having a reason to go out and have a good time. It isn't so damn structured."

It's a club, he claims, that will appeal to a younger, less tradi- tional crowd, people in their 20s and 30s, the people who hang plants in their renovated Capitol Hill and Adams-Morgan windows, the people who are associates, not partners, in the big-name law firms, people who are not Jody Powell but aides to Jody Powell, people, says Nathanson, "who in the next five years are going to be running this city."

Says Weitzman; "I would rather be at a party with one of the more interesting small businessmen in town than with one of the more wealthy people from Potomac or Middleburg who has nothing to say." And from Nathanson: "We just don't want warm bodies in this room. We want exciting people here."

Nonexciting, traditional people, they assert, are out -- even though some traditionalists, such as prominent hostess Ina Ginsburg, were sent invitations. She ignored hers.

"I don't lead the kind of life that calls for that type of club," she says. "And none of my friends have joined so far."

The idea for the Polo Club, which has nothing to do with horses, came from Curtis. He claims it all started back at Yale, where he was excluded from the secret and sought-after Skull and Bones Society.

"I really wanted to be invited," he says, mentioning that he ran for secretary of the Student Council. He lost. "But it wasn't your position, it was your contribution. I always felt that same sort of thing could be carried forward here."

So last fall, he ran the idea past Weitzman.

"Most of the other ideas Tommy had showed me were just gin-slinging little places," Weitzman says. "But this thing looked interesting."

Curtis then approached Nathanson and Boyle, a contract was signed, and the foursome was born. Now nobody is talking about the dollar value of the initial investment, although Curtis says they're currently $75,000 over budget.

That may be because the club, which will be open from 4 p.m. to 2 or 3 a.m. nightly for drinking, dining and dancing, is decorated with Chippendale-like furniture, Oriental vases, maroon-colored French carpet, a teak bar, oak floors, lots of feathers and a cigarette girl with the elegant name of Jennifer Toth.

"What we're trying to do is create a really classy, elegant kind of room," says Weitzman. "We've tried to encourage this as a place where people will come with an escort. It's not a 'Looking for Mr. Goodbar' kind of thing."

"I'm just hoping it won't be that kind of place," says Jo Carpenter, a press aide to Jody Powell who holds a brass membership card. "I'm newly divorced and I just decided it was time I got out a little bit."

The membership list, the investors say, was drawn up from their personal and business contacts. They claim it is eclectic, touching all professional groups in town. They also say it is secret, although names leaked out more than a week before the club opened.

Private clubs in Washington have a spotty, lackluster history. The Beautiful People this town has to offer are often politicans who work long hours and go home early. Patrons say that Pisces, which opened in 1975, is seldom crowded and that elan, which opened a year ago, is hardly the last word in glamor.

Will the Polo Club attract a stream of the younger version of Washington's Beautiful People, Curtis' "pretty young people" who often work just as hard and go home just as early as the others? Some, like Gandy Dancer owner Bill Paley Jr., say maybe ("if the right people are there, it could be a classic"), but others who were invited and declined say no.

"I don't need any more social life than the one I already have," says Ann Zill, 37, who manages General Motors heir Stewart Mott's $1 million annual philanthropy fund.

"I'm just not big on nightclubs," says Dr. Michael Halberstam, brother of the author. "I belong to a rowing club, a luncheon club, a tennis club, but not a boogie-til-you-puke disco club."

Still, the investors remain optimistic.

"There is a risk involved in it," says Weitzman, "but there's a risk in a lot of things."

"After all," adds Nathanson, 'If this club turns out to be a real turkey -- a trashy, sleazy kind of place -- it's going to have a significant impact on my credibility."