Shortly after President Reagan led the emotional ceremony marking the arrival of the coffins of the Americans killed last week in the U.S. Embassy bombing in Beirut, he declined to take any traditional humorous jabs at the White House press corps' annual social banquet.

"The original plan was that I would sing for my supper. Nancy and I had another sad journey that we had to make before coming here tonight. I hope you understand. I just don't feel, coming as we did from Andrews Air Force Base, I could stand up here," said Reagan, his voice heavy with emotion. "If you'll forgive us, we'll just hold onto the script and take a rain check, and I'll keep it for next year."

It was a solemn but understandable break with a Washington tradition, an evening when the president, or occasionally a substitute, hurls some good-natured zingers at the people who scrutinize him daily. Saturday night, the president received a five-minute standing ovation from the 2,000 guests at the White House Correspondents' Association dinner at the Washington Hilton. He and Nancy Reagan, who had both laughed heartily during comedian Mark Russell's political barbs, left after his brief remarks.

"He was very saddened by the Andrews ceremonies," said presidential counselor Edwin Meese after dinner, "and that was the reason he didn't feel he could speak in a humorous vein. He made up his own mind that that would be the way to go."

Thomas DeFrank of Newsweek, the outgoing president of the association, said that during dinner the president told him that "at one point at Andrews he got so choked up he couldn't speak." DeFrank had been alerted Saturday morning that the president's remarks might be less jocular than anticipated. "Michael Deaver White House deputy chief of staff told me early this morning he didn't know how the remarks would turn out. When we greeted the president it was obvious he was emotional."

The president's somber mood and sad composure changed much of the audience's merry spirits back to a business mood. "Before coming over, I had watched the Andrews ceremony on television and I almost felt sacrilegious putting on my tuxedo," said attorney Vernon Jordan, former executive director of the National Urban League. "The president did exactly the right thing. He did it just right. Now I wish he would do some other things right."

The dinner, which includes awards to outstanding journalists as well as speeches and comedy, attracts many Washington celebrities, from Cabinet members such as Attorney General William French Smith to national media newsmakers such as ABC's Barbara Walters to old-fashioned celebrities such as former heavyweight boxing champion Floyd Patterson. Patterson, now commissioner of the New York State Boxing Commission, was autographing programs, as was Lynda Johnson Robb, wife of the Virginia governor. James Brady, press secretary to the president, was busy discussing his physical therapy, as well as the fate of the Chicago Cubs.

Before Reagan spoke, Russell chopped away at politicians, reporters, newspapers, national pets such as the panda Ling-Ling and national attitudes. "I'm sort of bicoastal. Los Angeles--that's different, they don't really care what goes on here in Washington, D.C. They think Scoop Jackson is Reggie's . . . brother. They think the majority whip is a leather bar in Venice," said Russell.

And, of course, he took aim at James Watt, secretary of the Interior, whose recent views on music and the Beach Boys made front-page news everywhere. "He's not here tonight, he's tired; he personally slaughtered all the meat we have here tonight," said Russell. There were howls of laughter. "He's a man who once had a psychedelic experience listening to Lawrence Welk sing 'The Surrey With the Fringe on Top.' "

Russell's approach is quick fire and bipartisan. The boll weevils, the neoliberals and Atari Democrats got their share. "Mondale, it's the new Mondale, have you noticed? He speaks now with an authority never before perceived. And Mondale's speeches sound just as refreshing as they did on the day Hubert Humphrey wrote them." Scattered boos here.

"And Democratic senator from California Alan Cranston jogging his way into our hearts. He went down to Chicago and he endorsed Harold Washington. Mondale was in a bad light, he endorsed Dickey Daley. Then after the election Mondale tried to say, 'You mean Daley isn't the black one?' . . . Now here you had Harold Washington. All right, he had a little problem with taxes. He could have turned it around with a little reverse psychology. He could have said, 'I paid my dues, if nothing else.' Or a slogan, 'Vote for Washington, H and R Block's 18th reason.' "

John Glenn, the Ohio senator who entered the presidential race last week, Russell said, is the Democrats' best candidate. "It would drive the Republicans crazy, because John Glenn looks like a Republican. Nominate John Glenn. There were no stunt men on the Mercury space program."

Reagan was not spared. "A couple of weeks ago, the president was talking about El Salvador and he said, 'We are not talking about nutmeg here but about the security of the United States.' You know what they say: Today the nutmeg, tomorrow paprika. Remember, when you are president, you have to be a man for all seasons." The audience erupted into boos, and DeFrank waved his blue napkin as a truce bid. "I respect you for that," said Russell.

After the head table of 27 disbanded, the journalists and their guests went back to business as usual. Commerce Secretary Malcolm Baldrige spent almost an hour giving mini-briefings out the ballroom doors and down past the party suites. "This is their extra whack," said a smiling Baldrige. Susan Watters, of the Fairchild News Service, thumbed through the program and found where Eric Rosenberger, White House press coordinator for the Williamsburg Summit, was sitting. He hadn't returned her phone calls and she extracted a promise for a call this week.

And Gov. Charles Robb, who had led all the former Marines in the room in standing during the Marine band's brass rendition of that corps' anthem, was headed down the hall behind Charles Manatt, the chairman of the Democratic National Committee. Last week, the Committee chose San Francisco as the 1984 convention site, despite the combined hard sell by Mayor Marion Barry, Maryland Gov. Harry Hughes and Robb in favor of Washington.

"We did know we had no chance. Chuck Manatt had told us we weren't going to get it. But the effort created a little regional harmony," said Robb.