Republican George Bush vows to keep working hard until Nov. 8, determined to deny presidential rival Michael Dukakis a chance to live up to his prediction that the Democrats "will be the ones celebrating on Election Night."

Relaxing in Denver before returning to the campaign trail in Illinois and Missouri on Monday, Bush said he was encouraged but not overconfident after seeing polls showing his slim lead opening slightly over the Massachusetts governor.A tracking poll, conducted Thursday, Friday and Saturday and published in The Washington Times Monday, showed Bush leading Dukakis 48 percent to 47 percent. The poll also showed that 65 percent of the 1,002 people interviewed over the three days predict Bush will win the election, with 14 percent predicting Dukakis and 21 percent giving no answer. The survey interviewed about 335 voters nationally each day and has a margin of error of 3 percent.

The vice president promised to stay the course in the last three weeks of the White House race - and with that in mind he refused at a brief news conference Sunday to answer repeated questions about specifics of his budgetary plans.

"To suggest that we have to radically alter the game plan when you've seen the budget come definitively down in the last couple of years, I don't think I'm going to do that," Bush protested. "I've proposed a specific plan and I'm going to stay with it."

He pledged to comply with newly approved anti-drug legislation if elected, appointing as a Cabinet-level narcotics "czar" his own running mate, Indiana Sen. Dan Quayle. Under President Reagan, Bush has held a similar position as vice president - failing completely, according to Dukakis.

The Democrat, battling polls and perceptions suggesting Bush is bound for victory Nov. 8, pressed onward aggressively Sunday by telling a festive rally at Boston's Faneuil Hall that his rival apparently never has uttered the most important words a national leader must be able to say: "This is wrong."

"I may not express my feelings as eloquently as some," Dukakis conceded to the crowd, "but does anyone doubt what I would have said if I was in the room when they made those decisions to sell arms to the ayatollah, to put (Panama's Gen. Manuel) Noriega on the payroll, to veto civil rights and women's rights or to choose people like Dan Quayle, Ed Meese, James Watt and Robert Bork?

"I would have said three simple words: `This is wrong,' " the three-term governor continued. "When they put Noriega on the payroll, The New York Times knew he was selling drugs, NBC knew, the CIA knew and the National Security Council knew. But George Bush said he didn't know."

The hometown rally was the first Sunday campaign event in weeks for Dukakis, who lashed out at GOP predictions of a clear Bush victory ahead. He declared he would not roll over for the vice president _ and as if to prove his point, his aides had him flying Monday into the critical state of Ohio, where Sunday The Columbus Dispatch and The Cincinnati Enquirer endorsed Bush.

"The Republicans want to put you to sleep," Dukakis told the Faneuil Hall crowd. "They're already celebrating; they're popping champagne corks in their penthouses.

"But I've got news for those Republicans. We're going to be the ones celebrating on Election Night, because we're in a fight for America's future, and you'd better believe I'm not going to walk away from that fight, and I'm not going to walk away from the commitments of a lifetime.

"I started this campaign 18 months ago as an underdog, and I enter the last three weeks of this campaign as an underdog," he concluded.

Campaign manager Susan Estrich added later during an interview: "We started as an underdog, and we've always done our best as underdogs. We've been written off time and time again, and we've come back each time. So we look forward to the challenge of the last three weeks. There's no question that we're behind, but we're within striking distance, and we're going to fight very hard."

Estrich denied a report in The Washington Post Sunday saying that with time running out, Dukakis' organization has abandoned its plan to run a 50-state campaign so it can focus on 18 states with enough Electoral College votes to give the Democrat two more than the 270 needed to win election.

Dukakis' running mate, Texas Sen. Lloyd Bentsen, also disputed the report but conceded on CBS's "Face the Nation" program: "Of course you narrow and focus. There are times you use a shotgun approach and there are times when you rifle in. But we are going to win our fair share."