It happened all the time. A black man or woman would feel the injustice of racial discrimination and would walk in the door where Gwendolyn Cunningham worked, because this was the Washington office of the NAACP. And she would send them straight in to see the NAACP's legal counsel, Frank Pohlhaus.

"And a minute later, they'd come back out to me," she says, "and they'd say, 'I don't want to see him ! I don't want to see any white man."

Then she would remember the night of the riots in '68, when Pohlhaus spent all night in the Washington police station, bailing out young black men -- "even though some of them were wrong" -- and so she would always lean over her desk and, in harsh, hushed tones, hoping that Pohlhaus' feelings weren't already hurt, she would tell the person that if he wanted help he should turn around and walk back into Mr. Pohlhaus' office because he was the NAACP's only legal counsel in Washington.

For 14 years, Cunningham worked as Frank Pohlhaus' secretary and she came to regard him as "one of us." Many blacks did, especially those who worked with him during his 26 years with the National Association for the Advancement of Colored People. Those days are ending, with Polhaus' retirement from the association, and last night dozens of them -- including executive director Benjamin Hooks and former Washington bureau director Clarence Mitchell -- came to a reception in the Skyline Inn in his honor.

His retirement coincided with the gathering of NAACP representatives from 30 states, who have come to Washington for three days of lobbying on Capitol Hill in the face of what they consider their biggest challenge in recent years -- the Reagan administration's massive proposed cuts in the budgets of many social programs. It's the kind of fight that Pohlhaus has been involved in the last quarter-century, the kind that the NAACP has often won. Pohlhaus remembers some of those vividly, particularly the work on the Hill in 1964. The Civil Rights Bill.

"And when they wheeled in Sen. [Clair] Engle of California," he said, "he literally got off his deathbed. He died a few days later. But that day, we needed his vote to cut off the filibuster, and they wheeled him in for the vote. He couldn't talk. He might have had throat cancer, I'm not sure. But they called his name and he signaled by just raising his hand a little."

Pohlhaus, whose years were primarily centered around working on civil rights and social legislation, and who came to the NAACP from a distinguished Baltimore family, will never forget the exhilaration of winning that fight.

It overshadows, for obvious reasons, his memories of the night of the riots after the assassination of Rev. Martin Luther King, though the eeriness of that night has not yet escaped him, the drive through the deserted streets after the curfew. His daughter, Betsy, who was 11 then, lettered a sign to put in his windshield just before he hurried out the door. lawyer .That's all it had to say. It got him through.

"The streets were so lonely. It must have been 3 or 4 in the morning and I don't think I saw anyone else on the streets. And I remember coming home in the morning, driving past the buildings. They were burning like smokestacks."

Now the fight is back on the Hill, ground he knows well. He expects the poor and the hungry to lose the legislative battles in the coming months. "They've been whittling away at the social programs for several years, the busing thing, and others, but it wasn't a national threat, a political threat, until now. It's obvious we're going to lose some things, social programs. The threat is not so much on civil rights programs, though there is a threat there, too."

He expects the NAACP to lose its legislative battles for a few months, for the backward tide to slow, and then stop and turn around again. He suggested the turnaround would come after President Reagan's term.

"Four years," he told those who came to lobby, "is not that long a time."