When Marion Barry showed up in the North Portal Estates neighborhood a few weeks ago for a cookout, it was like old times. Here was the mayor, fighting for reelection, as the guest of two well-known city employes, Joe Yeldell and Bill Rumsey. In 1978 there was a strikingly similar party, but the guest of honor was then-incumbent mayor Walter Washington.

It has been the same story with many of the union endorsements that went to Washington four years ago. Now they go to Barry.

The extent to which Barry has followed in Washington's footsteps reached the absurd last Sunday when Barry, speaking at the church founded by Washington's father-in-law, even used Washington's favorite biblical story to do as Washington had done: let people know he is not ready to give up the mayor's job.

Barry and Washington, opponents in the 1978 race, have not spoken during the campaign.

Still, Barry, the one-time street activist, is closely following the lead of the older, more conservative Washington, whom he once condemned as "bumbling and stumbling." Barry, like Washington, is also winning support among people with an interest in government who feel secure in knowing the man in office, whether it is a Walter Washington or a Marion Barry. The way that Barry, like Washington in 1978, is using his incumbency to campaign for reelection is more apparent to many people in city government than the differences in the two men's politics.

Barry and Washington both used patronage and favors to woo people who are well-connected politically. But by dropping all pretensions about Congress controlling the city, Barry has endeared himself to even more District Building regulars.

He has made it clear that he has power to grant city contracts, give developers the right to develop city land, dispense licenses and permits, and help residents who support him.

With no large policy differences separating Barry and Harris, both solid liberal democrats, the issue of Barry's competence to run the city has become the main issue, but it is closely followed by talk about differences in the candidates' personalities and the promise of connections to one candidate or another have become factors in the race.

Barry is trying to persuade voters that he is the necessary stablizing force in a powerful city government that could be changed dramatically by the upcoming election with the council chair caught in a tough race, the Ward 1 seat open to a newcomer and at least one incumbent, Williams Spaulding in Ward 5, in a tough fight for reelection.

In his own reelection race, Barry is suggesting that his leading challenger, lawyer Patricia Roberts Harris, would mean more unsettling change for citizens, particularly those who know and have access to him.

That message has helped Barry win endorsements across the board, from political activists as well as ministers and businessmen.

Attorney Robert Linowes, a Barry supporter, offers one key to why keeping Barry in power is important to some people involved with the government.

"Marion is accessible and willing to be available to discuss issues and problems," said Linowes. "If he can get something done, he'll tell you. It's important to businessmen, as well as to civic organizations, to know how things can get done."

"There was access to Walter Washington ," Linowes added, "but it was more limited. He had Julian Dugas sitting next to him. . . . With Walter, when you walked out of his office you didn't know what was going to happen. Marion will give you his word."

Barry's has geared his emphasis on access to contrast with reports that Harris has a prickly personality and to raise questions about whom she would take into the District Building with her if she were elected.

Barry's followers have advanced the notion that access to Harris would be limited to the whites and federal government types that she worked well with in the past. And Barry's supporters have made a not-so-subtle suggestion that the white and federal government types make up the group that dictated law and policy in the District when a group of southern congressmen ran the city

Barry campaign tactics have prompted cynical responses from his opponents.

"They're saying the mayor may be bad, but he's delivering to us economically with jobs, contracts and the rest," said Charlene Drew Jarvis, the Ward 4 council member who is challenging Barry. "I've heard it here and there. It doesn't matter what his leadership is like so long as it benefits us individually."

Sharon Dixon, Harris' campaign director, said that Barry's campaign talk about access won't win votes.

"It depends on how long or short their the voters' memories are," she said. "The fact he has been so accessible and responsive suddenly to so many people should tell people who can see beyond their nose that pretty soon his accessibility will reach the point of diminishing returns. They'll have access, but access to what? The turnip will be bled to death."

At-large council member John Ray, who is also challenging Barry, questions whether Barry's accessibility extends beyond his business and political contacts to the average citizen.

"Political operatives and businessmen are talking about access," said Ray. "But the voters out there still can't get in. . . . People still say they're calling the District Building two to three times to even get the phone answered."