"Have you heard the one about Louie and the public accomodations act?" asked Harris Wofford, one of the Kennedy administration insiders, of Kenneth Clark, the pioneering psychologist, as they moved away from the cameras and the crowd at a reception in honor of that old Kennedy, Johnson and Carter hand, Louis Martin.

"It was the time of the Civil Rights Act of 1965 and there was a heated debate going on in the White House on whether public accomodations would be included," Wofford went on. "The argument was going in favor of not now. So Louie said to Bobby Kennedy, 'If there was a restaurant run by a white man, and he turned away my daughter, I would shoot him.' Kennedy was silent. And Louie said, 'If that's how I feel, imagine how those kids out in the street feel,'" recalled Wofford.

The air at the Joint Center for Political Studies dinner at the Washington Hilton last night was thick with legends about Martin, stories that told how he left his footprint on the last three decades' history. Also, the evening was thick with the social motions of a reunion, prompted by 1,000 people who have shared victories and wounds of politics.

Martin, who was a senior adviser to Jimmy Carter, bounded to the door when Edward Kennedy appeared, poking his finger at his chest. Kennedy asked about Martin's new vice presidency at Howard University, then turned quickly to Eddie Williams, the president of the Center, saying, "We've got to get working on that bilingual education motion." A few minutes later, Sargent Shriver hurried in, grabbed the venerable Dorothy Height around the shoulders, whispered to Martin, causing his bearish laugh to rattle, and kissed Martin's wife, Gertrude.

At the sidelines, Fred Silverman, the president of NBC, was marveling at all the political muscle when one of the organizers, Jayne Ikard, teased, "You arranged this so we would all miss the president being interviewed by Walter Cronkite, right?"

In this whirl of storytelling and levity, some natural animosities were left at the coat check. Del. Walter Fauntroy, the new chairman of the Congressional Black Caucus, was sitting with Arthur Teele, who headed up the black voters for Reagan-Bush. Bill Brock, the former head of the Republican National Committee, said, smiling, that his attendance was directed more toward the bipartisian public policy and research center than at the Democratic warrior, Martin. Mel Bradley and Thad Garrett, two architects of the new Republican policy, were rubbing elbows with Reps. Mickey Leland, Cardiss Collins, Julian Dixon and Parren Mitchell, who have all protested the Reagan administration's proposed social service cuts. Said Mitchell: "We might have to go to war with this administration."

But Bradley, who was delivering a message from President Reagan as the diners sat down to shish kebab and rice, joked about his time being cut. And Wiley Branton, the dean of the Howard University Law School, identified Thornton Bradshaw, the past president of the Atlantic Richfield Co., as the new chairman of RCA Corp., a post he hasn't assumed yet. So Thomas Donahue, the secretary-treasurer of the AFL-CIO, took the opportunity to mention the "millions of unemployed."

The evening was not without its messages. Martin, referring to Atlanta and Buffalo, spoke of the "resurgence of terrorism" and called for new and broader coalitions and the development of new political power. And Williams pleaded for constituent support for the Center similar to that for the Brookings Institution ad the American Enterprise Institute. "To insist that there is no longer a need for interventionist strategies to guarantee equal rights," he said in an apparent reference to President Reagan's budget message, "seems to me a dangerous misreading of the history and nature of the American dilemna."

The levity was swallowed up in the applause.