Jewell Robinson Shepperd has not been a supporter of Mayor Marion Barry, and she thought the manner in which the mayor grudgingly admitted last week that he had received a cut-rate mortgage left something to be desired. "The way that was handled was unfortunate," Shepperd said the other day.

But she is hesitant to criticize Barry publicly these days, she said, because among some blacks in town, Barry is viewed as a black man under attack by the press, and you don't jump on a brother when he's under the white man's gun.

"A lot of black people are going to close ranks and are going to make absolutely no criticism when criticism would be appropriate," Shepperd, a former television talk show host, said. "You don't want people to just say, 'White folks have been doing it for years' when that's not really the issue. But there's a danger that you divide the community along racial lines when you appear to attack its leader on racial terms."

Consultant Timothy Jenkins was not a Barry supporter either during last year's campaign. But then the president of the Greater Washington Board of Trade took issue with Barry's clarion call for a financial share for blacks in downtown development, even if that equity came with little or no money up front. Jenkins and other black businessmen jumped to the mayor's defense -- partly in their own self-interest.

"There was a surging move by the black business community to come to his rescue," Jenkins said. "There were a number of meetings to rally 'round the flag and say let's not allow the administration to be criticized for its opposition to the idea that money should flow the way it's always flowed."

Even labor leader William Lucy, a stalwart in the political camp of former Mayor Walter E. Washington, suggests that The Washington Post in general and columnist Richard Cohen in particular appear to be "doing a job on Marion."

This especially seems to be the case, Lucy said, because of publication of a series of articles alleging the theft and misappropriation of $600,000 by a spinoff of Pride, Inc., the black self-help group that Barry helped to found.

"What they are doing to Marion ain't no news to nobody. Pride is nothing new to nobody," Lucy said. "The argument is why now as opposed to before? I can't put a finger on it unless they're pressuring him or trying to get him to shift."

A year ago, underdog Marion Barry was vigorously endorsed by the editorial page of The Washington Post and wound up winning a close three-way contest with little help from the black community.

Now The Washington Post, through what some perceive as a rapid-fire succession of "negative" stories on the Barry adminstration in the news pages is giving Barry another political plus, this time within the black community.

In the view of many blacks, he has become a symbol of what some expect to be a short-lived Reconstruction in the nation's capital, to be followed by a hasty return to the white-dominated status quo -- and white-run city government -- of not too long ago.

Lillian Wiggins, a columnist for the Washington Afro-American, calls it "the master plan." She writes about it in sometimes extreme tones that nevertheless convey the private sentiments of a broad spectrum of blacks, from Gold Coast lawyers and Southeast politicans to mid-level government bureaucrats, college students and civil rights activists -- and some of Barry's own advisers.

"Many residents believe that the Marion Barry era may be the last time Washington will have a black mayor," Wiggins wrote last week. "That's debatable, but if the powers that be have any say in the matter . . . this may very well be the last black mayor . . .

"If negative programming and characterization of black leadership are allowed to continue in the city of Washington and especially in the black community there is a strong possibility of the 'master plan' which I have so often spoken about maturing in 1980."

Not everyone sees the coming of a white apocalypse that soon. There's not even an election for mayor scheduled that year. Some push back the date as far as 1986.

Yet, closely entwined in every version of the conspiracy theory is the city's news media -- especially The Washington Post, which has in recent years been held in suspicion, distrust and awe in some sectors of the black community.

Post editors emphasize that the news department and the editorial page are two distinct operations. Further, they say, the newspaper is not out to "get" anyone. The Post's reporting is based on fair and unprejudiced journalistic principles. In their view, the conspiracy theory is absurd.

Yet, in the minds of some blacks who have prospered under black-dominated elective government, such explanations are equally absurd. They don't believe that lines are drawn between functions at a newspaper. They think editorial writers, news reporters, photographers, columnists and headline writers play in well-orchestrated concert under the heavy baton of the publisher.

The power of the press is considered much greater than the spirit of the people. Every item -- from columns to captions -- is looked upon as some form of corporate manifesto.

They seem to believe that the function of the press -- and black reporters at white newspapers -- is to be an ally of the politicians in power. Stories are thus either "positive" or "negative," part of the solution or part of the problem. That is a view expressed by Mayor Barry himself.

Sometimes they will concede that there are sound journalistic principles underlying a story. But they also read that story from a different perspective and draw different conclusions -- right or wrong.

So some black professionals, who are rising in their careers the way Barry is rising in politics, are falling in line behind the mayor as they perceive him to be under attack.

They didn't like his campaign for mayor. They were embarassed by the way he explained his support for a financial share for blacks. They believe the published reports that Barry's former wife, Mary Treadwell, and two others allegedly stole and misappropriated $600,000 from the federal government and low income tenants in the Clifton Terrace apartments complex. And they think it was kind of stupid for Barry to accept a hefty discount on his mortgage.

But when all of these things appear in print and it seems like there is a battle between The Post and Barry, they feel they have more in common with Barry and side with the brother.

One prominent black lawyer, who asked not to be named, sees a whole generation of Washington blacks afraid of losing power before they even get to use it. It is a fear even more acute, the lawyer said, than that Jews have over anything that even smacks of anti-Semitism.

What is seldom mentioned is that The Washington Post has developed a reputation for rigorous and aggressive scrutiny for public figures from Warren Burger, Richard Nixon and Spiro Agnew to Bert Lance, Jimmy Carter and Larry Hogan. Try selling the Post-is-soft-on-white-folks line to Marvin Mandel.

Presidents, judges, governors, county executives and, yes, mayors, have immense power over the lives of the people they serve and the citizens ought to know what they are up to. Is there any reason why residents of the District of Columbia should be told less just because the mayor is black?