"We couldn't have held the 20th century without him," Sen. Edward M. Kennedy (D-Mass.) ruled from his podium last night. He was speaking of W. Averell Harriman, the statesman whose 90th birthday was celebrated by America's Democratic establishment last night.

Members of five White House administrations, the Senate and the House and some of the nation's governors were among the 1,500 who came to Harriman's birthday party, a fete that turned into a flexing demonstration of Democratic might. Washington Hilton clubrooms were packed with the shadows of politics past.

"Cyyyyyyyyy!" former secretary of state Edmund Muskie called to another former secretary of state, Cyrus Vance. They shook hands vigorously like two good pols, just one of the reunions occurring almost as often as the drink orders.

It was all for a man who has been called "the most durable link between the United States and the rest of the western world," a diplomat who was with Winston Churchill when the Japanese bombed Pearl Harbor, a key negotiator at the Yalta conference, an administrator of the Marshall Plan and an adviser who has known every president since Calvin Coolidge.

Last night, five speakers honored him -- John Kenneth Galbraith, Clark Clifford, Kennedy, Lady Bird Johnson and Walter Mondale -- representing the five presidents he has served.

"I was so surprised to hear everybody say such nice things about me tonight," Harriman said, softly but clearly, after the speeches. "It leaves me with a greater responsibility than when I came -- to do more for our nation, to take on more tasks."

"Early on in our administration we sent Harriman over to see Tito," Mondale recalled during the pre-dinner cocktail reception. "They were old friends. When Harriman came back, he wrote a memo to the president that began, 'I'm very disturbed because Tito is beginning to show his age.' We loved it."

In the last ten years, I guess I've seen most of the important political characters -- Benes, de Gaulle, Chiang, Adenauer, de Gasperi, and all the rest. I've seen Stalin more than any other foreigner has, you know. Some name did come up the other day -- someone I'd never met. I've forgotten who it was for the instant. Oh, yes. Nehru.

-- W. Averell Harriman quoted by a friend, in The New Yorker, 1952

The VIP reception for Harriman got under way in the Cabinet Room of the Hilton at 7, and by 7:15 there was an astonishing collection of famous people. It seemed that every other face has been on a magazine cover or at least a newspaper front page. A small selection: historian Arthur Schlesinger Jr., former Carter campaign chairman Robert Strauss, Evangeline Bruce, actor Paul Newman, House Speaker Tip O'Neill and Democratic stalwarts Clayton and Polly Fritchey.

"I was scared to death of him," said Polly Fritchey, recalling the first time she met Harriman. "He was so glamorous. I met him at the Bruces', and I think I was silent. He was marvelous-looking. He was unbelievable."

"He has the most distinguished manners of anyone I've ever known," said Schlesinger. "They're manners of an old school. Except at croquet. At croquet he's ruthless."

In the midst of the crush was Harriman, accepting congratulations, handshakes and kisses from friends.

"He said he was so nervous when we were getting ready," said his wife, Pamela. "And I said, 'You, nervous? You're never nervous.' "

Khrushchev got right down to business and said: "Since we have decided to have a test ban, let us sign now and fill in the details later." I agreed and handed him a blank sheet of paper, saying: "Fine, you sign first."

-- "America and Russia in a Changing World," by W. Averell Harriman, 1971

The birthday party was in fact a fund-raiser for the Democratic National Committee and Democrats for the '80s, Pamela Harriman's political action committee. The gross was estimated at $950,000, the result of the $500-a-head tickets (some guests, however, were there as friends of the Harriman family and so didn't pay). There was additional money provided by the sale of the table centerpieces for $100 each. They were railroad cars, symbols of Harriman's days as chairman of the board of the Union Pacific. For $150, the contributor received a model of the New York skyline, signifying Harriman's birthplace, as well as the railroad cars.

"Please make checks payable to 'Averell Harriman Birthday,' " the small cards on the tables instructed.

The party might have turned into a roast of the Republicans, but Democrats minded their manners. It was Harriman himself who said, "The Democratic Party is the creator of new ideas . . . a Republican fears that the Democratic Party is going to bring change to this country."

Pamela Harriman, who organized the event, was congratulated almost as often as her husband was wished 'happy birthday,' which actually falls on Sunday. "You did it, darling," said Sen. Ernest Hollings (D-S.C.) to Pamela Harriman. "This is your night."

Strauss, a close friend of Pamela Harriman's, was asked how the birthday party had turned into a fund-raiser.

"It was always a fund-raiser," he replied brightly. "Pamela always wanted to do that. And he Averell wanted to do that."

As guests filed down to the ballroom for dinner, their eyes were caught by a stage decorated with giant black-and-white cutouts of Harriman in various stages of his life. There was one of him skiing, sunglasses and shirt unbuttoned, at Sun Valley, the resort he founded; there was another of the Union Pacific; and there was a third of Harriman at the 1943 first meeting of the Big Three -- Stalin, Roosevelt and Churchill at Tehran.

Harriman spent most weekends at Chequers, the Prime Minister's country estate. So close had they become that Churchill thought nothing one dawn of bursting into Harriman's bedroom -- in a yellow sweater, short nightshirt, pink legs exposed -- to shout that the famous British ship the Hood had been sunk. Harriman went with Churchill to Bristol, a city still smoldering from incendiary bombs. As their train pulled out of the station, Churchill and Harriman watched the crowds waving goodbye. Suddenly, tears were streaming down Churchill's face. "He picked up a newspaper to hide his face. 'They have such confidence,' he said to me. 'It is a grave responsibility.' " -- The Washington Post, 1975

Kennedy's speech got the best response from the crowd, especially the anecdote about how Harriman got his nickname.

"President Kennedy was well aware of Averell's famous and quite selective hearing aid which, as we all know, conveniently turns itself on and off. But once during a meeting at the White House, the hearing aid actually failed, and as the president started to talk, so did Assistant Secretary of State Harriman -- who just kept talking. And afterwards, a worried official asked the president if he was annoyed. 'Of course not,' Jack said: 'I enjoy watching Averell in a meeting more than anyone else. He sits there with his head down, and you might think he's asleep. But then someone says something foolish, and he bites his head off with one snap, like a crocodile.' And that is the story of how the story of how the crocodile was named."

"I'm looking forward to Averell's 100th birthday," Kennedy said. "Fritz Mondale will be here representing the Carter administration -- and I'll be here representing the Kennedy administration."

Earlier, during the cocktail reception, Paul Newman's presence caused a brief stir. It is something that happens in a town used to a steady diet of politicians. He knows Harriman from the United Nations.

"His wisdom kept pouring out of his ears," recalled Newman. "I was so humbled by him. He devoted his whole life and his energies to holding this planet together."

In another corner of the room, speaker Tip O'Neill: "We had a terrific supper at his house one night, 15 or 18 years ago," he said. "It was me and him and the Russian ambassador. It was the most fascinating evening I've ever had discussing international affairs."

On Stalin, Harriman wrote:

It is hard for me to reconcile the courtesy and consideration that he showed me personally with the ghastly cruelty of his wholesale liquidations. Others, who did not know him personally, see only the tyrant in Stalin. I saw the other side as well -- his high intelligence, that fantastic grip of detail, his shrewdness and the surprising human sensitivity that he was capable of showing, at least in the war years. I found him better informed than Roosevelt, more realistic than Churchill, in some ways the most effective of the war leaders. At the same time he was, of course, a murderous tyrant. I must confess that for me Stalin remains the most inscrutable and contradictory character that I have known -- and leave the judgment to history.

-- "Special Envoy to Churchill and Stalin," by W. Averell Harriman and Elie Abel, 1975

Right before dinner, the Democratic congressional leadership wheeled out a four-tiered yellow birthday cake, covered with candles. Tip O'Neill led the crowd in "Happy Birthday." Paul Newman escorted Harriman up to the stage to blow out the candles.

Pamela Harriman, asked if she ever thought her husband would make it to 90, replied: "I never thought of him not being 100."