Mayor Marion Barry confirmed yesterday that Ivanhoe Donaldson, deputy mayor for economic development and Barry's chief political adviser, plans to leave government late this year--possibly to work on a presidential campaign or run his own consulting business.

"It's no secret he's leaving, but the question is whether it's October, November or December," Barry said during an interview. "He would have left earlier if I hadn't been holding on to him like glue."

Donaldson, a shrewd and often brutally effective political operative who has been Barry's alter ego for the past two decades, repeated his earlier statements that he was ready to leave city government and said he may devote full time to private business, including possibly reactivating a consulting firm called First City Corp. that he helped form last year.

He said he also is considering going to work for a Democratic presidential candidate and has held conversations with aides to the Rev. Jesse Jackson, who is contemplating entering the race, and former vice president Walter F. Mondale, a leading Democratic candidate.

"I think the dialogue that Jesse Jackson has brought within the Democratic Party is a good and positive one," but "he hasn't made any decision about what he wants to do," Donaldson said. "I've talked to Mondale's people too. I like the vice president." Donaldson said the subject of a job did not come up in his conversation with Mondale's camp.

Donaldson will become the second top-level government official and Barry confidante to depart this year, after the mayor's reelection and a major government reorganization that Donaldson helped to orchestrate.

Elijah B. Rogers, another principal architect of Barry's first term, stepped down as city administrator in late May to become an assistant managing partner in the Washington office of Alexander Grant & Co., a major accounting firm.

The close relationship between Donaldson and Barry dates back to their days together in the civil rights movement during the early 1960s. Donaldson managed Barry's 1974 campaign for the D.C. City Council and later ran Barry's hard-fought victory over Walter E. Washington and Sterling Tucker in the 1978 Democratic mayoral race.

During Barry's first term, Donaldson served as the mayor's general assistant and head of a D.C. government cash management team. Later, Donaldson was assigned to assume control of the troubled Department of Employment Services, a post he held until he resigned in May of last year to manage Barry's reelection campaign.

Donaldson headed Barry's transition team and worked with Rogers in devising the reorganization plan that included the creation of three deputy mayors for administration, finance and economic development to share the power previously entrusted solely to city administrator Rogers.

Barry said yesterday that while Donaldson would be difficult to replace, "the government isn't going to stop running."

Donaldson said that when he left city government in the spring of last year to manage Barry's reelection campaign, he had no intention of returning. A month before he stepped down as acting director of the Department of Employment Services, he set up First City Corp., which he said was intended to be a consulting firm.

Donaldson said in a financial disclosure statement he filed with the city earlier this year that he received $10,000 in fees from First City Corp. Yesterday, Donaldson said those funds were his salary as head of Barry's transition team, money that he had paid into the corporation.

"That's how I wanted to be paid," he said. "I was laying the foundation for a consulting business that was going to be my own. I was First City Corp." Later, he said, when he decided to return to government, he withdrew the $10,000. Since then, he said, the corporation has been dormant. "I put all that on the back burner" after becoming deputy mayor, Donaldson said.

The firm was incorporated by Jeanette Michael, who at the time served as Donaldson's attorney and who is now employed full time as general counsel to the D.C. Lottery Board.

According to records filed with the D.C. Recorder of Deeds on April 26, 1982, Michael and two other people who later became city employes, Marshall Brown and Allison Page, were listed as the initial directors and incorporators.

Donaldson said yesterday: "Incorporators don't mean anything. The fact that all [are now] city employes is really irrelevant. They weren't at that point in time."