Four hours after denouncing negative campaigning as the politics of the past, Bill Bradley traveled to an elementary school here to denounce Vice President Gore for a 15-year-old vote on a Senate amendment that would have raised the price of cigarettes.

Bradley immediately faced a fusillade of questions about why this vote was fair game for him to attack, when just three days ago, he had replied to a challenge by Gore to his record on farm issues by declaring that voters care about the future, not 15-year-old votes.

"If you believe something over time and you feel deeply about it, then you have to be consistent over time," Bradley said. "I've been consistent over time with regard to tobacco. And I think this illustrates that he hasn't."

The amendment, which was sponsored by Bradley when he was a senator from New Jersey, failed by two votes. It would have canceled a scheduled reduction in the tobacco tax in order to prevent an increase in Medicare premiums.

"It lays out a very clear point in time where there was a disagreement over who supported Big Tobacco and who supported Medicare," Bradley said after lecturing a gym full of fourth- and fifth-graders on the lethal effects of smoking.

That point in time was 1985, and Gore explained in an emotional speech to the Democratic National Convention in 1996 that he had changed his mind about the danger of smoking after his only sibling, Nancy Gore Hunger, died of lung cancer. Tennessee, which Gore represented in the Senate, is the nation's third-largest tobacco producer. In New Jersey, the leading crop is cranberries.

A fact sheet distributed by Bradley also took Gore to task for a 1988 letter to the editor of the Arkansas Democrat-Gazette opposing a ban on tobacco advertising. At a news conference in the library of Wallace Elementary School here, Bradley acknowledged that he and Gore no longer disagree on the issue.

"I'm very glad that he's evolved on this issue," Bradley said. "I think that he's in the right place now, and I think that's important. But I also think that we can always do more."

Gore, campaigning in Davenport, Iowa, said Bradley's attack "smacks of sort of desperate negative campaigning."

"I'm not sure why he would do something like that except that the caucuses are approaching and he's engaging in negative campaigning," Gore said. "You know, he said he wouldn't do that, but I guess he changed his mind."

Gore's press secretary, Chris Lehane, released a statement labeled "Dollar Bill's Phony Promises," mocking Bradley's pledge to run a "different kind of campaign."

"The purported philosopher-king is turning into the professor of petulance in the heat of the campaign spotlight," Lehane said earlier.

In this presidential race, Gore is relying on some of the tobacco industry's most successful consultants, including media strategist Carter Eskew and pollster Harrison Hickman.

Bradley, who was thrown badly on the defensive by his failure to answer questions about a flood relief vote that came up during a debate on Saturday, has been growing more aggressive by the day. At a town meeting Monday night in Boone, he twice referred to the opposition as "Gore-istas."

Bradley defended his decision to resurrect an old Gore vote when he had protested the same tactic at the debate. "What the consistent position here is is my advocacy to have very strong anti-tobacco legislation--that's the story here," he said.

Bradley suggested that today's salvo marked a major change in the campaign's tone. "Sometime, this was going to become competitive," he said. "I said through the campaign that I was going to be positive--I still am going to be positive, I'm still going to try to give people something to vote for. But I think that it's absurd to get into the question of saying that anything anybody ever did, any position anybody ever took is somehow or another off limits."

Staff writer Ceci Connolly with Gore contributed to this report.

CAPTION: Democratic presidential hopeful Bill Bradley leaves a chartered plane in Des Moines before speaking to elementary school students there on the dangers of smoking.