DENVER, AUG. 21 -- A burning summer rumor that spread like wildfire through the political world this week was quickly doused today as ex-senator Gary Hart declared through a key aide that he will not reenter the race for the 1988 Democratic presidential nomination.

But in the wake of this latest unlikely twist in the seemingly endless Hart-for-president saga, friends and political allies of the onetime front-runner said Hart still yearns for the White House and still believes he can be a major player in Democratic politics in 1992 or beyond.

While journalists in three countries searched for him, Hart -- who was reported variously to be in Ireland, Britain and the United States -- refused any public comment on the predictions from his former campaign manager that he will get back into the 1988 nomination sweepstakes. According to Irish Radio, Hart told a reporter there, "I want to make it clear that I have no comment to make . . . . I'm not going to get into a debate here in Ireland. I will neither confirm or deny."

He then did his best to duck reporters and get on with an Irish vacation.

But Hart sent back word through a spokesman that there is no basis for the speculation from former campaign manager William Dixon that Hart will reenter the Democratic race this fall.

The ex-candidate's longtime political aide, Bill Shore, said he telephoned Hart in Ireland in the wee hours of Friday to ask about the statements from Dixon that Hart will reenter the race. Dixon said earlier this week that he considered it "likely" that Hart would reenter the race within 30 to 60 days.

As relayed by Shore, Hart's response to the Dixon statements was: "Oh, no, no, no. You should be very unambiguous with people who ask. I'm not a candidate. I don't have any intention of being a candidate."

It appeared to be a fairly standard political rite: Trial balloon is launched, trial balloon is shot down, and everybody moves on to the next rumor. But the fascination with Hart's political and private lives meant this relatively short-lived rumor would not be set quickly aside.

The former senator's friends and adversaries today pondered aloud over the genesis of Dixon's prediction and what it might mean about Hart's political future. Hart went from front-runner to washout in the Democratic presidential race during one tumultuous week last spring when he was confronted with accusations of extramarital relationships. In the weeks after his bitter speech of withdrawal, there was a diaspora of Hart campaign workers and contributors out to the campaigns of other Democratic contenders.

But a hard core of Hart people has remained true to the old cause, according to the candidate's friends. They have been calling Hart at his law office in Denver to argue that none of the other Democratic hopefuls offers the thoughtful leadership he could provide. "Their message is pretty plain," said John Emerson, who had been Hart's deputy campaign manager. "You know, 'Gary, you've got to get back in this thing.' "

Other Hart allies said the prime movers in the push for reentry were San Diego hotel magnate Larry Lawrence and Denver attorney Norm Brownstein, both veteran Hart backers and fund-raisers. Neither responded to calls today.

Hart's response to the appeals was ambiguous, his friends said. For one thing, Hart thinks that the political obituaries that followed his withdrawal were premature. "The basic view is, if the guy handles things right this year, he's got a shot at running {for president} in the future," Emerson said.

Hart has started building a schedule of public appearances around the country, beginning with a foreign policy lecture in Philadelphia on Sept. 10. He has made it clear to his friends and family that he wants to be a key voice on policy issues in the Democratic Party during the 1988 campaign and afterward.

Over lunch with some former campaign staffers a few weeks back, Hart started talking about his future as a public figure, according to one person who was at the table. "What you saw was that this guy doesn't believe that it's over for him," the staffer said.

Moreover, Hart was evidently not inclined to spurn outright the suggestion of old friends who were trying to advance his interests. "Whether or not it was a good idea for Hart to get back in," said Eli Segal, one of the ex-candidate's chief political aides, "there's no reason why you should just cut off your friends and financial supporters without listening to them."

It seems clear that only a small minority of Hart backers saw any virtues in the reentry proposal. Once the idea became publicly known, the response of Hart associates generally ranged from "bizarre" to "astounding."

"It's absurd," said Hart's former policy chief, David Dreyer, in a comment typical of Hart staffers' reactions. "If this is a trial balloon," Dreyer went on, "it's the Hindenburg of trial balloons."

But the arguments of those calling for Hart to reenter the campaign were strengthened when a Gallup poll on Democrats' presidential preferences commissioned by The Nation magazine showed Hart leading all the other Democratic presidential candidates in July, more than two months after his campaign went down in flames. Columns in The Nation and The Washington Post's Outlook section argued that Hart was still one of the Democratic Party's hottest properties.

As is inevitable in politics, money was another consideration. If Hart were to become a 1988 candidate again, he would presumably qualify for about $1 million in federal matching funds, money that his campaign has been denied on grounds he is not an active candidate.

Dixon appeared tonight to back off somewhat in response to Shore's denial that Hart would revive his campaign. He said his earlier statement was "a guess" based on conversations he has had this summer with Hart, the most recent of which occurred 11 days ago. Asked how he reached the conclusion Hart would run, Dixon said, "It's one of those conclusions that is so much easier to arrive at than to defend."

He said that he has not been urging Hart to get back into the race.

It is unclear whether Hart gave the reentry plan serious thought. But by last week, the discussion was prevalent enough in the community of Hart backers that Dixon, the former campaign manager, was talking up the idea among liberal activists and in calls to The Washigton Post and other media outlets.

Dixon thus sparked the wildfire that burst into brief political glory and was then doused by Hart's long-distance disavowal. Staff writer Paul Taylor contributed to this report.