On the day of the last Democratic debate before Tuesday's primary here and just a day after his advisers promised he would become more aggressive, Bill Bradley backed away today from a radio interviewer's invitation to discuss past controversies about Vice President Gore.

Gore and his campaign team, however, did not hesitate to launch a few preemptive strikes against Bradley--on his opposition to the 1996 welfare reform bill and on his stepped-up critique of Gore--before their debate tonight.

When interviewer Dan Pierce of WGIR-AM in Manchester told Bradley that he did not appear ready to "wade in there and start hacking," the former New Jersey senator responded: "I think that you have to decide how you're going to run your campaign. I think it's more important to give something for people to vote for than to vote against."

Pierce, who described himself as a conservative Republican, tried to bait Bradley by bringing up such catch phrases from the 1996 fund-raising scandals as "Buddhist nuns and the vow of poverty" and "no controlling legal authority."

"I think those are legitimate issues you raise," Bradley said. "But the question is, what're you going to do with your time on the stump every day? And what I want to do with my time on the stump every day is to lay out a positive vision for the future of this country, because I think that also is a contrast between a politics that's nothing but tactics, and a politics that's based on ideals and beliefs."

Bradley added, "I think the way campaigns have been run tends to depress turnout because they become so negative. That doesn't mean that the points you made aren't valid, nor that at some point that might not be something to explore."

Bradley began his day at the Greater Manchester Family YMCA, where a class of children age 3 to 6 quizzed him on whether he was wearing boots (no--wingtips), whether he likes the sun (yes) and whether he likes the ocean (yes, too).

In preparation for tonight's debate, Bradley's campaign handed out a 13-page digest of articles and broadcasts that criticized Gore, with sections titled "The Media Responds to Gore's Negative Campaign" and "The Media Responds to Gore's Distortions."

Also today, Bradley won the endorsement of James Tobin, an economist at Yale University who won the Nobel Prize for economics in 1981. Bradley began airing a 60-second radio ad in which male and female announcers alternate reading from the endorsements Bradley has received from newspapers serving New Hampshire.

This afternoon, Nebraska Sen. Bob Kerrey and Niki Tsongas, widow of Paul Tsongas, a Democratic senator from Massachusetts who was a 1992 presidential candidate, held a news conference to criticize Gore for negative campaigning.

At a briefing for reporters, Bradley's press secretary, Eric Hauser, defended Bradley's light schedule, which is in sharp contrast to Gore's frenetic pace. "I can't comment on what the vice president is doing, but Bradley has a lot of zip going," Hauser said.

At least for today, Gore kept to a light schedule with only event, a tour of Electropac Co., a circuit board maker in Manchester. There, Gore brought up Bradley's opposition to the welfare reform legislation that passed in 1996.

"I would like to challenge Senator Bradley to change his position and recognize at long last that the welfare reform he vigorously opposed is a success," Gore said. Mocking his rival's claims to be future-oriented, he said that on the subject of welfare Bradley "saw a brick door" where the Clinton administration "saw a doorway to opportunity for millions" of Americans.

The Gore team also brought out Bill Shaheen, husband of the governor, to rebut complaints by the Bradley camp that the vice president's campaign has turned nasty. "I've seen negative campaigns, and I can tell you this is not a negative campaign," said Shaheen, Gore's chairman here. "This is a campaign on issues."

With the debate coming at such a late hour, Gore previewed a bit of his strategy earlier in the day, urging his Democratic rival to embrace his proposal for cracking down on deadbeat dads and expanding assistance for people shifting from welfare to work.

"I would call upon him, and I will do so in the debate this evening, to change his position, get with the program of welfare reform that works and go the next step and endorse the proposal that I'm making for a new generation of welfare reform and keep the economy moving strongly," he said to a crowd that held just as many reporters as Electropac workers.

On several fronts, the Gore team is building its final New Hampshire push around the theme of economic success. In his appearances, in the debate tonight and in two new television ads, the vice president touts the booming economy and argues that he is the candidate best positioned to "keep the prosperity going," as he puts it.

In one new 30-second ad, Gore boasts that he was part of the team that helped to balance the budget and turn massive debts into federal surpluses.

Asked whether the new rosy surplus projections would alter his own campaign proposals, Gore said, "Whatever [the numbers] turn out to be, our priority should be paying down the debt, making sure we keep the economy strong, keep interest rates low and give the Fed plenty of flexibility to keep monetary policy supportive of the continuation of this economic recovery."

A new poll here gives Gore an edge in next Tuesday's primary. Although there are still five full days of campaigning left, the vice president's aides have begun discussing ways to force Bradley out of the contest in early March.