Justice Department guidelines encourage prosecutors to ask public officials to resign from office as part of plea negotiations, even though the U.S. Attorney's Office here maintains that the resignation of D.C. Mayor Marion Barry would be "irrelevant" to the case.

With jury selection in Barry's trial only two days away, reports have surfaced that Barry's resignation would be a key element of any plea bargain acceptable to U.S. Attorney Jay B. Stephens.

A spokeswoman for Stephens disputed those reports last night, calling Barry's resignation "irrelevant to the prosecution of this case." Barry has said he will not step down, and in recent months has called suggestions that he resign "unconscionable, "unprecedented" and an effort to "dictate the politics of this city."

Many Barry allies, in particular black activists, say the idea of the government forcing Barry out is repugnant and call it an attempt to disenfranchise voters.

Stephens hinted earlier that resignation might help Barry in plea negotiations. But Stephens, having been roundly criticized for those statements, is now mum on the subject.

The U.S. Attorneys' Manual, which guides prosecutors nationwide, encourages them "to continue to consider voluntary offers of resignation from office as a desirable feature in plea agreements . . . . Resignation from office and/or withdrawal from elective candidacy remain appropriate and desirable objectives in plea negotiations with public officials who are charged with federal offenses that focus on abuse of the office{s} involved."

These guidelines were written in response to a 1982 decision by a federal judge in New York who invalidated parts of a plea bargain requiring then-Rep. Frederick Richmond (D-N.Y.) to resign and withdraw from a campaign.

Chief Judge Jack Weinstein of the U.S. District Court for the Eastern District of New York ruled that the agreement was in conflict with the "fundamental right of the people to elect their representatives." The Richmond case is binding only in the Eastern District of New York.

And it does not hold sway in the rest of the nation. Lawyers and former prosecutors interviewed said that when plea bargaining begins in such a case, the public official may dabble with the idea of resigning, but rarely takes the step.

"I prosecuted a number of congressmen and federal judges," said Reid Weingarten, who helped run the Justice Department's Public Integrity Section for 10 years, "and in virtually every case, resignation was on the table." But Weingarten said that in each of his cases, the elected official couldn't abide the thought of surrendering office, and went to trial.

Weingarten declined to discuss specific cases, but among the officials he prosecuted were then-Reps. John W. Jenrette (D-S.C.) and George Hansen (R-Idaho), both convicted and sentenced to prison.

The most famous public official who left office in a plea agreement is Vice President Agnew. He stepped down after a federal judge, in tense and secretive negotiations with prosecutors and defense attorneys, agreed not to give Agnew prison time. At the time, U.S. Attorney Elliot Richardson said the agreement "spared the nation the prolonged agony" of a trial.

In Barry's case, sources say that several major stumbling blocks remain, including Stephens's reported insistence that Barry plead guilty to a felony, which would almost certainly bring prison time.

Barry's reluctance may be bolstered additionally by his expressed belief that his trial may end in a hung jury.

Stephens previously has been sensitive to charges of political interference in such cases. In the 1988 guilty plea of the American Samoa's delegate to Congress, Fofo I.F. Sunia, prosecutors tried to avoid the appearance that they were standing in for the electorate, said sources familiar with the case. During plea negotiations, the sources said, Sunia agreed to resign, but prosecutors did not want to include that in the formal plea agreement given the judge.

Defense attorney Herbert "Jack" Miller, who represented President Nixon in his final days in office, said it is not unusual for resignation to be an "understanding that never really surfaces as part of the deal." As a practical matter, he says, if a person pleads guilty, "chances are that he is going to leave the office in any event."

But Miller expressed a common sentiment: that it is "inappropriate" for a prosecutor to include stepping down as part of a formal plea arrangment.

Several lawyers, including former U.S. attorney Joseph E. diGenova, say they see no problem with extracting a promise to step down. "The defendant has every right in the world to say I refuse that offer and go to trial," diGenova said.

But sometimes the pressure is so great, and the consequences so dire, that public officials feel they have no option but to give up their offices, said Gary Colliaf, an attorney for Mike Roark, former mayor of Charleston, W.Va. Hounded for years by rumors of cocaine use, Roark was indicted in 1987 on charges of conspiracy, drug possession and distribution.

Moments before opening arguments were to begin, it was announced that Roark had agreed to plead guilty to six misdemeanor counts of cocaine possession and to resign. Colliaf said Roark's decision came after days of bargaining sessions that turned on Roark's willingness to resign.

As part of the plea agreement, prosecutors made no recommendation about the sentencing. Roark was sentenced to 179 days in prison and fined $5,000.

"It was insisted upon as a condition of the plea agreement," Colliaf said. "We would rather not have had that in the plea agreement . . . . Nobody likes to be told he has to quit his job in 10 days or five days . . . . {But} it's pretty hard to risk a felony conviction."