The Democrats came to town today and, before their midterm convention even began, got down to business with one behemoth movable cocktail party where half a dozen presidential hopefuls made their debuts. The White House, of course, was never mentioned.

Sen. Edward M. Kennedy (D-Mass.) said he was only campaigning for his Massachusetts race at the Iowa State reception at 7 p.m., former vice president Walter Mondale's reception at 6 p.m. and Philadelphia Mayor Bill Green's reception at 4 p.m. Sen. John Glenn (D-Ohio), creating a new compound adjective by announcing he was "press available," answered questions about his candidacy at a 3:30 p.m. press conference with a little laugh and then, "We're keeping all the options open." Sen. Gary Hart (D-Colo.) responded to the same question with "I haven't decided yet," although minutes earlier an aide watching Hart sign autographs under hot television lights had beamed: "I think he's kinda into it."

A good 6,000 delegates, journalists and Democratic junkies are here for the three-day conference. The floor debate on seven issues has been controlled by the Democratic National Committee, so many have decided to let the weekend be what it really is anyway--a giant reunion of old faces, many of whom haven't seen each other since the New York convention in 1980. They gossiped, they clogged traffic and, for half an hour at the Bellevue Stratford Hotel, got stuck in the elevator.

That was because everybody was trying to get up to the 19th floor for Mondale's reception, the premier social event of the evening. (Some thought it would be the Iowa reception, that being the first caucus-state reception, but they were wrong.) The other elevators, overstuffed with Democrats, for some peculiar reason stopped at every single floor on the way up.

"God, do I need a drink," somebody said on the 11th.

"I've had nightmares about this," another said on the 16th.

"What a zoo," they said on the 19th. The place was mobbed.

Mondale and his wife, Joan, managed a receiving line that made several bends before it wandered out the door. The TV cameras made everything look important--including Mondale, who, according to his law partner John Reilly, "picked up a lot today. You could tell."

"Has he lost some weight?" somebody asked.

"Nah," said a staffer. "But he had his nose fixed."

Suddenly, Kennedy arrived. It was just like what happened in the early days of the 1980 campaign: The reporters swooped, the women got agitated and Kennedy, slowly moving across the floor in the usual halo of television lights, left Mondale in the dust. But the Mondale people said they'd invited him. Reilly was asked how he thought it looked when Kennedy, who has 45 points on the latest Gallup Poll to Mondale's 10, upstaged Mondale at his own party. "I think it looks wonderful," said Reilly, flatly.

But a Kennedy supporter went further. "Oh, this is awesome!" said Kevin Convery, 18, a DNC press aide. "I'm so psyched. It's an excellent political move."

Meanwhile, many of the nearly 1,000 delegates were literally panting their way up the 18 flights. One, caught mid-gasp, said with sweat trickling down his cheek, "I've come up to see Fritz." Not everybody was so pleasant. "Only 10 more floors to go," said one man, who was struggling on the ninth. "I'm going to become a Republican. This is ridiculous."

Much of the traffic flow was coming from Green's reception, the first big party of the night. It was in the Bellevue Stratford's ballroom, an elaborate, chandeliered expanse of cheese and fruit and gooey sculptures in the form of a bald eagle and Liberty Bell. Everybody wondered what they were made of.

"Lard," said Tony De Martinis, a Pennsylvania delegate and the Mercer County chairman of the state Democratic party. "I'm glad my county doesn't have to pick up the tab for this," he said, gesturing toward the buffet. "If I had something like this in my county, which has 15 1/2 percent unemployment, I wouldn't have a job."

Several hours later, the Iowa reception at the Philadelphia Centre Hotel was warming up. It was in a plain old party room with a cash bar and Ritz crackers. To the naked eye, it looked like just a bunch of nice people getting together.

But strategically situated throughout the room were several power centers: Ed Campbell, the former state chairman of the Iowa Democratic Party whose wife, Bonnie, made him take off his Mondale button when Kennedy swept through; Des Moines Register political editor Bob Flansburg, to whom every right-thinking candidate must pay respects; and Art Hedburg, a Des Moines lawyer and one of Kennedy's early supporters. After Kennedy shook his hand and moved on this time, Hedburg sighed, "I'm getting to be an old man. I don't know if I can do it with him again."

The Iowa reception was in the Pennsylvania East Room of the Philadelphia Centre, which resulted in several party-goers getting it confused with an event in the hotel's Pennsylvania West Room. Hart actually stuck his head in the wrong door, but quickly withdrew when he saw a Greek bishop kissing the hands of some women. It was a meeting of the Panepirotic Federation of America and Canada, which is a group from the northwest part of Greece.