The first time Al Gore ran for president, his mother slipped him a note as he prepared for an Iowa debate: "Smile, Relax, Attack." Twelve years later, the dutiful son is still following her advice.

Today, as the sitting vice president locked in an unexpectedly tight nomination fight, Gore has returned to the offensive, hammering away at his rivals with a zeal and doggedness unmatched by any other candidate in the race.

Gore has accused former senator Bill Bradley of siding with drugmakers over average Americans, scheming to eliminate Medicaid and quietly considering a tax increase. He says Texas Gov. George W. Bush's tax cuts benefit the rich at the expense of fiscal discipline. And in private moments, Gore whispers that John McCain is awfully unpopular among his Senate colleagues.

In recent days, Gore has swept his hand across his throat to graphically illustrate what he believes Bradley would do to nursing home standards and he has derided Bush for crafting a tax cut that, per person, is worth no more than the price of a Diet Coke each week. Yesterday, in an interview with the Associated Press, he assailed his Democratic rival for "flying off the handle" in response to criticism of his policy proposals.

"The competition is healthy," Gore said in a recent interview, clearly relishing life in the political boxing ring.

Ridiculed for years as President Clinton's stiff and silent understudy, the Al Gore on the campaign trail is aggressive, outspoken and increasingly eager to draw sharp -- some would suggest unfair -- contrasts with his opponents. The approach, reminiscent of his 1988 effort, has rejuvenated the Gore team, forced Bradley to abandon his unique zen-like style and revived the ancient political debate over whether campaigning by critique works, particularly in a year when voters seem to want nice.

"Voters want to be able to compare, but they want to be able to compare the facts, not distortions," said Bradley spokesman Eric Hauser, who has been frustrated by the daily Gore onslaught. "Candor begets trust and voters want to be able to trust their leaders and being straight with them generates trust."

The vice president has also surrounded himself with a cadre of operatives well-versed in the art of political thrust and parry. The recent arrival of trench warriors such as Bob Shrum, Tad Devine, Carter Eskew and Harrison Hickman has reinforced Gore's pugnacious instincts.

These advisers defend the strategy by arguing that the public wants help deciphering candidates' positions. "Voters like a real debate on issues," said Shrum. "Al Gore is conducting a campaign about things that are fundamental to voters: health care, education, economic policy. Bradley is conducting a campaign largely about the notion he has big ideas and therefore should get elected."

Perhaps more importantly, the advisers believe the approach works.

"We are doing better," said Shrum, citing recent New Hampshire polls in which Gore has closed the gap with Bradley. "The reason Bradley has been spending an enormous amount of money [on advertising] is he's worried about what is happening in New Hampshire."

Gore has balanced his attacks in recent days with new, more positive television ads on health care and education. And some political operatives say it is unlikely that Gore's attacks will generate the kind of backlash that Steve Forbes felt when he attacked Robert J. Dole in 1996. In that race, Pat Buchanan was the beneficiary of the Forbes-Dole spat.

"There are only two of them" in this year's Democratic contest, said Democratic political consultant Bill Carrick. "That allows you to be aggressive and not suffer the consequences of potentially offending somebody who doesn't like `negative campaigning' because they don't have anywhere else to go."

But other analysts say Gore is walking a fine line. Suggesting there is a "gap in the public's perception of Bradley," Pew Research Center pollster Andrew Kohut said Gore "rightly wants to change that evaluation." But the danger, he added, is that it "could be seen as too negative and the same old typical politicking."

Gerry Chervinsky, a Boston-based pollster, said the feisty Gore is faring only slightly better than the boring Gore. "It has stopped the flow of people who were abandoning him," said Chervinsky, whose new poll in New Hampshire has the two Democrats in a statistical dead heat. "I don't think it's drawing people to him."

Raymond Strother, a Gore media consultant in 1988, said he fears Gore's attacks may backfire. "I'm worried about him going too far," said Strother, now a lecturer at Harvard University. "Bradley is running a nonaggressive strategy that makes Al Gore look like not only an aggressor but maybe an unfair aggressor."

In a five-page document titled "Just the Facts," the Bradley campaign went point-by-point through a series of what it termed Gore misstatements, some about himself and some about his opponent.

The memo cites Gore's boast that "unlike senator Bradley, I was a cosponsor" of the McCain-Feingold campaign finance legislation, even though the bill was not filed until September 1995, almost three years after Gore left the Senate. And it revives the vice president's claim to have "found a little place in upstate New York called Love Canal," a statement for which he apologized for the next day.

More significantly, Gore has stretched the truth on policy matters, the Bradley camp charged. They say Gore is wrong when he accuses Bradley of wanting to abolish federal nursing home standards. And after lashing out at Bradley for acknowledging he may need to raise taxes to pay for his health care plan, Gore too said he would not make a no-new-taxes pledge. "I am ruling them out under circumstances that approximate what we have today," Gore said. "Nobody has a crystal ball."

For now, the Gore team is happy to simply shift the political chatter away from its internal machinations and onto policy.

"He's energized because he feels the campaign has finally come around to what he visualized the campaign would be: a real argument about substance," said Gore friend and former adviser Bob Squier.

Even some who have felt the sting of Gore's earlier attacks say it appears he has learned to moderate his criticism. "In 1988, he was very aggressive and borderline nasty," said Carrick, who, as Rep. Richard A. Gephardt's campaign manager, complained bitterly about Gore's attacks.

In that race, it was Gore who first pinned rival Michael S. Dukakis for a controversial prison furlough program, and it was Gore's ad campaign that said of Gephardt: "He'll say or do anything to get elected." Among his attacks, Gore charged that Gephardt supported Ronald Reagan's 1981 tax cuts, opposed an increase in the minimum wage and switched his position on abortion (which Gore had also done).

In fact, he went after all his Democratic rivals. "The race comes down to this," one 1988 Gore ad said. "Dick Gephardt voted against raising the minimum wage, against working people, but for Reagan's corporate giveaways. Mike Dukakis, whose inexperience has led Time magazine to call his foreign policy `mushy and unsophisticated.' Jesse Jackson, who has never worked in government. . . . "

In some measure, the Gore strategy worked. Gephardt was so tarnished he dropped out of the race. But it was a Pyrrhic victory: Dukakis won the nomination -- not Al Gore.

Staff researcher Ben White contributed to this report.