The Rev. Jesse Jackson is a step closer to declaring his presidential candidacy, and all signs indicate he intends to make his bid within the Democratic Party - not as an independent. Mr. Jackson would be the eighth hopeful to declare for the Democratic nomination.
Some sources close to the Jackson operation, including M. Carl Holman of the National Urban Coalition, say Jackson's announcement will come before the end of the month. In fact, the public relations office of Gary, Ind., Mayor Richard G. Hatcher said at one point that Jackson would announce his candidacy as soon as Saturday, Oct. 15, at a museum fund-raiser there. Neither Mayor Hatcher nor Jackson was available for comment.
Leaders of the National Association for the Advancement of Colored People (NAACP) and the National Urban League have heard reports of the ''coming statement,'' but continue to oppose the Jackson candidacy.
''The NAACP stands by its board statement of last April of not endorsing any candidate,'' says Denton Watson, press spokesman. Benjamin L. Hooks, executive director, has labeled a black candidacy ''fantasy.''
A Jackson campaign would be powered by a cross-country coalition of clergy and grass-roots support offering financial aid and manpower, Jackson backers say. His ''rainbow coalition'' includes people of different races, political views, and religious backgrounds, they say.
A Jackson declaration is not on the formal agenda for the gathering tomorrow at the Genesis Convention Center. The occasion will be a fund-raiser to finance the construction of a proposed National Civil Rights Museum and Hall of Fame in Gary. But Jackson has scheduled a 6 p.m. press conference on Saturday, when he will make some sort of announcement, according to Jackson's presidential advisory committee in Gary.
Mr. Holman, who has continually supported a black candidacy, says, ''Rumors that he will announce are spreading in New York. It has to happen sometime, somewhere, and it could be in Gary. Jesse has raised 'rainbow coalition' money on Wall Street and in Texas (recently).''
Although key supporters will not acknowledge Jackson's announcement, certain go-ahead signals are seen:
* A Jesse Jackson presidential advisory committee has set up headquarters in downtown Gary.
* Ever since Jackson swept through Boston a week ago in a four-hour round of receptions, fund-raisers, and a rally, he has not made a major public appearance. Earlier there were public appearances in Los Angeles, Detroit, New York City, New Hampshire, and Boston.
* Both Jackson and Gary Mayor Hatcher of are on indefinite leave from their positions at Operation PUSH (People United to Serve Humanity). Jackson is president, and Hatcher, the board chairman of the organization. Hatcher is considered the likely manager of a Jackson-for-president campaign.
* A Committee to Draft Jesse, headed by Bishop H. H. Brookens of the African Methodist Episcopal Church based in Washington, is pledged to support Jackson.
Says a leading Boston clergyman, the Rev. Charles Stith, pastor of Union United Methodist Church, ''We are committed to raise money, recruit workers, to go the whole line to help Jesse nationwide.''