With 3 1/2 weeks left before election day, the long-sputtering campaign of Virginia Democrat Andrew P. Miller finally has started to roll, fueled by what his advisers view as two potentially high-octane issues: the integrity of Miller's opponent, John W. Warner, and the legacy of retiring Sen. William L. Scott.

In speech after speech last week, from Tidewater to the mountains, the Democratic candidate emerged from his obsession with facts and figures to call forth the ghosts of Virginia history that traditionally touch the state's political soul.

Those ghosts, Miller suggested, have been dishonored by Warner's "very casual attitude toward the truth" and by the "inexcusable . . . irresponsibility" of Scott, who complaining of illness, left the Senate Wednesday and went on a vacation,missing numerous votes.

Noting "substantial discrepancies" between Warner's recent statements about his past and what Miller said is part of the public record, the Democrat told an audience in Newport News Thursday that "Virginia deserves better than that . . . One of the things this state has stood for time and time again is integrity . . ."

Friday in Hampton, he called a special news conference to deplore Scott's "irresponsibility" and to remind the voters that Scott had endorsed Warner and appeared with him at a fund raiser only days ago.

"The Republican Party gave us Bill Scott . . . The Republican Party is now offering us my opponent. I say on Nov. 7 Virginians will remember this record," Miller said.

Warner, speaking in Staunton yesterday, implied that Miller has been taking the low road in making personal attacks on him in the campaign. "You know I used to go to college down here in Washington and Lee about the time my opponent was north in Princeton," Warner said in a speech to a Virginia Jaycees convention. "And, Andy, we used to take what we called the old low road, Rte. 11. to get down there.

"Listening to some of those personal comments you made about me, I tell you that I haven't been taking the low road in this campaign. I'm taking the high road - Interstate 81 - to get up there.

"Our campaign is predicated on issues. I stick to issues because that's what will control the ballot box on Nov. 7," Warner said.

Warner's comment was greeted with cheers and laughter from the 450 Jaycees and Jaycettes at a convention luncheon. The crowd gave the Republican a somewhat warmer response than they did to Miller.

Warner also said Miller is misstating his position on taxes and federal budget reductions. Warner said he has consistently supported an across-the-board tax reduction" coupled with reductions in federal spending and waste."

Miller's comments on Scott and integrity inevitably make a restive crowd attentive. They also bring joy to Miller supporters, many of whom have anguished over their candidate's tendency to argue his case in the language and lecturing style of an appellate lawyer.

"Andy tends to talk too much about nuances that many voters either don't care about or can't understand," said one Democrat at a fund raiser Thursday night in McLean. "But this integrity thing hits everyone. That's what Virginia is supposed to be all about."

Since Monday, when Miller borached the issue, a Miller staffer in Richmond said, "It's a whole new campaign."

The sharpened focus of the Miller campaign part luck and part design. The candidate and his advisers long have sensed an uneasiness with Warner among the state's older, more traditional conservatives, and have pondered how to exploit it.

Warner may have played into their hands by compiling during the past two months a record of erratic and sometimes contradictory public statements.

Miller has concentrated chiefly on four incidents in the Warner campaign.

A Washington television interview after which Warner tried unsuccessfully to have a controversial statement edited out of a tape interview, in which he said that while serving as secretary of the Navy he tried to moderate racial change in the Navy.

A statement last week in Norfolk in which warner said he "didn't have and didn't want" the endorsement of organized labor and "had no memory" of ever asking for it. Minutes of his meeting with labor leaders last August show that Warner made a formal appeal for endorsement from both the leadership and the rank and file.

A statement in Roanoke two weeks ago in which Warner said he voted for Sen. Harry F. Byrd Jr. (I-Va.) in 1970. Financial reports show Warner donated $1,000 to Byrd's Republican opponent, Ray Garland, that year and nothing to Byrd.

Statements in his campaign literature picturing Warner as a "surprisingly unpolitical man" who has "never asked for a tradeoff" in return for his political support. Warner conceded in a television debate that he had arranged negotiations with former president Nixon to have himself named undersecretary of the Navy in return for Warner's efforts in Nixon's 1968 campaign.

"When you have that kind of pattern emerging," I think it's time to step back and look at the candidate in question," Miller said in Petersburg Wednesday.

"I ask you," Miller said in Newport News the next day, "to pay close attention not just to the issues in this campaign, but to the way the candidates conduct themselves . . .

"When my opponent got the nomination in the middle of August, I had only met him four or five times before . . . He had not been involved in Virginia affairs and I did not know him, just as most Virginians didn't know him.

"But as this campaign goes on," Miller said, "we're getting a much clearer picture of the type of individual he is."

Miller's attacks on Warner are all the more noteworthy because they are, for him, unusual. Miller is not by nature an attacker and, in fact, has been criticized in some Virginia political circles for not going after his opponent, even when justified.

Post mortems on his loss last year to Henry E. Howell in the gubernatorial primary usually blamed that debacle on his refusal to challenge a bizarre Howell speech that attempted to tie Miller to anti-Semitism or a Howell interview in which he called Miller inexperienced.

A number of people close to Miller have blamed his reluctance to take the offensive on his boyhood memories of the bitter personal attacks against his father, the late Col. Francis Miller, when the elder Miller challenged the Byrd organization in the late 1940s and early 1950s.

Miller does not deny that analysis. He suggests that responsible public servants, particularly in Virginia, should strive for a higher type of campaign.

Even his attacks themselves carry a kind of moral imperative, as if to say that Warner's behavior might be all right for Washington, but Virginians should demand something better.

Miller's attacks on Scott carry the same sense of heritage betrayed. "I wish to express to you today my grave concern over the lack of conscientiousness displayed as recently as yesterday by the present junior senator," Miller told his news conference Friday.

Noting Scott's reputation for junketing ("He has visited 38 countries at taxpayer expense, some of them more than once") Miller added: "I assume if Bill Scott had decided to run again he would be the nominee of the Republican party."