Two of the Democratic Party's biggest figures have scheduled television appearances early next week to talk about plans for the 1988 presidential campaign, and if the prevailing political intelligence holds, Jesse L. Jackson will be getting in and Gary Hart staying out.

Jackson will appear on "Good Morning America" on Monday to make his intentions known, then take part in Labor Day functions in Pittsburgh, Cleveland and New York. The three-state swing follows two fund-raising successes this past weekend in New York and Chicago that, aides said, brought Jackson's Exploratory Committee's haul to the $1 million goal he had set for Labor Day.

"He is feeling very encouraged," said spokesman Frank Watkins, who added that, even if Jackson gives a green light Monday, he will not make a formal declaration of candidacy for another month.

Meantime, Hart has agreed to appear Tuesday night on ABC News' "Nightline" to clear up the confusion former campaign manager William Dixon created two weeks ago by predicting that the one-time Democratic front-runner would get back into the race this fall.

As has become the pattern the past 10 days, there were conflicting reports from among self-styled Hart insiders yesterday about what the erstwhile Democratic front-runner intends to say.

John Emerson, the Los Angeles lawyer who was deputy campaign manager of Hart's 1988 effort, said that he will not get back in, and his views were echoed by the most former Hart aides contacted by The Washington Post. Emerson, who has been talking to Hart regularly, said the former senator wants to "convey his true feelings about what happened" in May when he quit the race six days after The Miami Herald reported he had spent a night with with Miami actress-model Donna Rice.

But San Diego hotel owner Larry Lawrence, a longtime Hart friend and financial supporter, said he expects the Coloradan to announce that he will reenter the campaign "on a low-key basis." Lawrence said he has been urging Hart for weeks to do that. Most other friends and supporters, however, have been urging the opposite.

One theory circulating among political insiders yesterday was that Hart would apologize for his lapses in judgment and ask the public that he and his family be allowed to put the matter behind them. He would then begin to speak out on public policy issues, not as a candidate, but also not without hope that he might set off a groundswell of support to get back into the race.

Whatever he says on Tuesday, Hart plans to raise his profile this fall. He will address the World Affairs Council in Philadelphia next Thursday to discuss U.S.-Soviet relations, and is expected to be the main speaker Sept. 21 at a fund-raiser for defeated New York Senate candidate Mark Green.

Jackson, by contrast, has been been behaving like a candidate all year. Since Hart got out, Jackson has led most of the Democratic polls, although his support level registers in the mid-teens. He is the only Democratic candidate who has sought national office before, garnering about 18 percent of the primary and caucus vote in 1984.

In his first campaign, Jackson's focus on the unfairness of the nominating rules and on the need for voting rights enforcements gave "a lot of people the impression that what he was doing was running against the party," Watkins said.

This time, his message has shifted to economic populism, focusing on the plight of unions losing jobs and farmers being driven off their land. In 1983-84, Watkins estimated, Jackson spent 90 percent of his campaign in the black community, where he had to shore up his base. This past year he has spent "maybe 40 percent in the white community," where he is finding more forums open. He has, for example, addressed the joint legislatures of eight states.

Jackson's fund-raising is already running well ahead of his 1983-84 pace. "We were basically broke the day we announced in 1983," Watkins said. This time, last weekend's events in Chicago, attended by Mayor Harold Washington and others, and in New York, featuring entertainers Bill Cosby and Roberta Flack and hosted by businessman Percy Sutton, obtained more than $350,000. They were Jackson's two biggest fund-raisers ever.