Wherever in the world the Soviet diplomats go, the desperate Jews follow.

They are the refugee Jews who now live in the United States or Israel and who left behind parents, brothers and sisters in the Soviet Union. Their relatives are less well-known than the dozens of famous refuseniks who have been released with great fanfare recently. And they fear that their loved ones are on the verge of being forgotten.

They have pleaded their case at summits in Geneva and Reykjavik, and at virtually every bilateral session throughout the world in the last two years. Now the same group is descending on Washington to buttonhole members of Congress, reporters and Soviet officials here for the Reagan-Gorbachev summit.

Somehow these newcomers to the West -- many of them here only a few months and unlearned in the ways of American politics and the media -- have mastered the art of persuasion.

"I need all the help I can get here," said Galina Khatutsky, a tiny, red-haired woman who trembled as she addressed 10 television cameras, 30 reporters and four U.S. senators at a Capitol Hill news conference this week. She was pleading for release of her father, Yuri Zieman, a computer scientist who has been trying to leave for 10 years and is in need of brain surgery. "The only help is constant pressure from the West."

Anna Charny-Blank doesn't have any public relations experience, either. But, only four months after her release from the Soviet Union, she is tireless -- and eloquent -- in pleading the case of her father Benjamin Charny, 50, a Soviet mathematician dying of cancer.

"You do what you have to do," said Charny-Blank, who lives in Boston and hands out to reporters fuzzy Polaroid shots of her teary-eyed father at their Moscow parting last summer. "If you have a dying father in Moscow, even if you're the dumbest person on earth, you know what to do."

Everywhere they go, the refusenik family members hold up enlarged photographs of their loved ones, distribute hand-scrawled news releases and give impromptu talks to anyone who will listen. Sometimes when the news television lights go on, they start with the routine news conference spiel, then burst into tears.

Their emotional appeals have gained attention on Capitol Hill. Senators and representatives -- including some from districts without large Jewish constituencies -- have organized news conferences and circulated numerous petitions on their behalf.

"They're incredibly articulate, and very compelling," said Rep. Steny H. Hoyer (D-Md.), one of Congress' most active members in helping refusenik families. "They energize and get the attention of people in public office who interface with the Soviets. They really make an impact."

Yesterday, several members of Congress met with Soviet Embassy counselor Gueorgui Markowsov in the office of Rep. Albert G. Bustamante (D-Tex.) to ask for the release of Vladimir Dashevsky, a Hebrew teacher in Moscow suffering from heart and kidney ailments. The Soviet official expressed displeasure that the politicians had invited a television crew to the meeting, and was described by a participant as "giving the party line."

But Bustamante said the very fact of the meeting -- a group of powerful U.S. politicians pressing a Soviet representative on the eve of the summit on behalf of a little-known man half a world away -- was testament to the powerful moral force of Dashevsky's daughter, Ira, who traveled from her home in Israel for the meeting. "These are individuals capable of powerfully motivating people on behalf of their families," he said.

Khatutsky, Charny-Blank, Dashevsky and the others are practicing a kind of international guerrilla campaign of public relations with the Soviets. Where the Soviets show up to negotiate and extend their policy of glasnost, the families are there to test its limits. At Geneva and Reykjavik, some of them interrupted news briefings by Soviet officials and held up portraits of their relatives.

They describe it as a victory if they can sidle up to a high Soviet official and catch his ear. Last year, after the Iceland summit, several supplicants had the good fortune to board a New York-bound plane bearing Soviet Foreign Ministry spokesman Gennady Gerasimov, who spoke to them for 40 minutes.

Jewish activists say they'll never know the precise reasons, but within months after the flight, some of their relatives, including Vladimir Slepak -- who had been denied a visa for a record 17 years -- were released.

Now the desperate ones are in Washington for the summit, which they believe presents new hope for them on the theory that the Soviets will want to present themselves as reasonable and interested in reform.

"The summit provides a window of opportunity for international publicity for them," said Samuel Sislen, an official with the Jewish Community Council of Greater Washington and an activist for Soviet Jewry. "Using moments of bilateral contact is extremely important to them in their efforts . . . . Their struggle is ongoing and all-consuming."

One of the movement's recent victories showed a family overcoming the bureaucratic obstacles in its path -- but the story ended in tragedy.

Mikhail Shirman, a Soviet refugee, was weakened and bald from chemotherapy when he traveled to Reykjavik to beg Soviet officials to allow his sister to move to Israel because she was the only person who could give him bone marrow transplants for his leukemia. Because the Soviets refused to let her husband go with her, Shirman's sister would not leave. Shirman told reporters he wanted to confront "the man who is murdering me" -- Gorbachev -- and later was seen at the summit huddled with a top Soviet representative.

Later, the sister and her husband were allowed to leave and the delicate operations were performed. But it was too late -- Shirman died a few months later.

The cases of the ill refuseniks are among those that have grabbed the most attention here.

One is Benjamin Charny, whose daughter Anna pleads for his release at every turn.

A well-known Soviet mathematician, he and his wife Yadwiga applied to emigrate in 1979, but have known only desolation since then. They and their family members were fired from their prestigious jobs, refused work everywhere, then threatened with arrest by Soviet police for "parasitism" for not having a job.

Several years ago, Charny was diagnosed as having cancer, a condition that has worsened. Now he is bedridden, and has a severe heart condition. Soviet doctors, having available few of the advanced treatment techniques practiced in the United States, say his prospects are dim, but American doctors who have examined him say much could be done for him here.

Still, the Soviets refuse to let him leave, and won't let him apply until the mid-1990s. Officials cite the same grounds used in many other cases, that he has knowledge of "state secrets." But the Charny family is dumbfounded by the allegation, saying that his last classified work, on a Soviet space research project, ended in the early 1960s and is obsolete in relation to current research.

"How can a man as mortally sick as my father be a security risk?" Charny-Blank asked. "My parents are all alone. Everyone knows how important it is for a cancer patient to be at peace with his family . . . . I'm absolutely desperate, and won't stand a day without doing something."

Igor Tufeld -- who left his elderly parents, engineer Vladimir and mathematics teacher Isolde, in Moscow 10 years ago -- is just as desperate. Both of his parents are severely ill and are still being denied emigration rights on grounds of possessing secrets. His mother has a brain tumor, can't walk and has problems speaking.

"Our relatives desperately need your help," he told a reporter this week. "What good does it do to have them dying there?"