MANCHESTER, N.H. (AP) _ Bob Dole and Pat Buchanan clashed repeatedly over taxes, trade and tactics Thursday night as eight Republican presidential hopfuls offered competing conservative agendas in a crackling debate five days before New Hampshire's pivotal primary.

Looking to revive his troubled campaign, publisher Steve Forbes said he had made a mistake airing negative ads. Yet in the next breath he labeled Dole a tax raiser and raised ethical questions about the financial dealings of former Tennessee Gov. Lamar Alexander.

Firing back, Alexander said his personal dealings were detailed in tax returns he has released to the public. ``Steve, why don't you disclose your taxes?'' Alexander said. Forbes has refused to do so, and after the debate, Forbes suggested Alexander change his campaign theme song to ``Alexander's Ragtime Scam.''

The urgent tone reflected the volatility of the New Hampshire race _ and the entire GOP presidential campaign _ heading into the final weekend before Tuesday's vote.

Most of the shots were directed at Dole, Buchanan and Alexander _ the top three finishers in Monday's Iowa caucuses. No knockout blows were landed, but the pointed salvos suggested a tumultuous weekend ahead. ``I've been shot at a lot tonight but I've been in combat before,'' Dole joked, nervously.

Several long shots complained about that, warning that biggest winner of the bitter primary battle might be the incumbent Democrat. ``We have to stop tearing at one another,'' said California Rep. Robert Dornan.

One potential voter agreed. ``I think the White House must be gleeful,'' said Lovering Hayward, 54, an independent of Dunbarton, N.H. ``I don't see a candidate here that I am comfortable with,'' said Abigail Beutler, 65, a Republican from Nashua.

While the candidates sparred over the tone and tactics of the campaign, they were in broad agreement over why a Republican president would be better than a second Clinton term: the budget would be balanced, taxes cut and reformed, more power shifted to state and local governments.

They also agreed health care should be more accessible and easier to carry from job to job, and that the Social Security system will need to be restructured. On that point, Dole said raising the retirement age was worth considering; Forbes called for allowing younger workers to put some payroll deductions into private investments instead of government trust funds.

Buchanan voiced the hardest line against illegal immigration, promising a security fence along the border. Alexander suggested a new branch of the armed forces for border patrol.

Hoping to overtake Dole in the final days here, Alexander closed by turning to the wobbly front-runner and said, ```Bob, we respect you but you are not the man to have in that debate with President Clinton and not the man to be the first president of the next century.''

Dole had a different view, saying he was the superior candidate for those ``looking for a mainstream conservative candidate with answers and ideas going into the next century.''

Buchanan closed with a line borrowed from John Kennedy's 1960 campaign: ``I believe that I am ready.'' He also delivered a defiant defense of campaign co-chairman Larry Pratt who took a leave of absence earlier in the day after a report linked him to white supremicist and militia groups.

Dole and Buchanan are in a tight race for first place here, and some new polls suggest Alexander's third-place showing in Iowa last week has him inching up. Forbes has fallen in recent days from challenging Dole to fighting for third, and he hoped the debate would halt his slide.

In dramatic evidence of how the race has changed since last month, Forbes was a lonely man for much of the night, taking only a few gentle jabs after he and his flat-tax plan faced sharp, repeated attacks last time.

The post-debate spin session again proved the high stakes: several candidates ventured into the press room to continue making their arguments. Forbes again attacked Alexander for turning a $1 investment with poltically connected friends into a quick $620,000 profit, mockingly suggesting Alexander could write for Forbes magazine.

From the outset of the debate, the candidates sparred over campaign tactics, with Buchanan and Alexander lashing at Dole for launching ads critical of their views.

The biggest policy difference came on the issue of trade, with Buchanan roundly criticized for proposing to cancel global trade deals and slap high tarrifs on foreign goods.

``Pat is off on this isolationist kick,'' Dole said at one point. At another, he said ``Pat has gotten carried away tonight.''

Returning fire, Buchanan said Dole had supported tax increases, a point raised later by Forbes, too.

In the trade fight, Dole got plenty of help. Alexander, Forbes, and Indiana Sen. Dick Lugar warned Buchanan's protectionist views would kill many more jobs than they saved. The last time such views were popular, ``We got a Great Depression,'' Forbes said.

But Buchanan didn''t flinch.

``I plead guilty to wanting to protect American workers making $10 an hour,'' he said. Alan Keyes and Morry Taylor took Buchanan's side in this fight.

Sparking a colorful exchange, Buchanan said Dole had sold out American workers and catered to big banks by supporting a $50 billion bailout of Mexico's government.

``Mexico will pay it back,'' Dole said, arguing the deal protected American exports by stabilizing the Mexican government and economy.

``Lotsa luck,'' Buchanan said. ``You're not going to get a dime back.''

Forbes said Republican leadership was necessary to revive an economy that was ``like a patient with walking pneumonia. We're out of bed but we're not well.''

Forbes said his flat tax plan was superior to the tax cuts advocated by congressional Republicans.

Antiabortion candidate Keyes, however, said Republicans were short-sighted to focus on economics, blaming America's angst on the decline of the two-parent family.

Just hours after Dole launched a TV ad labeling Alexander a liberal on taxes, spending and crime, the former Tennessee governor opened the debate by confronting the fragile front-runner.

``Senator Dole, you are better than your negative ads,'' Alexander said. ``Why don't you pull them?''

Dole recalled in response that for all his complaining, it was Alexander who launched the first negative ad of the campaign, months ago against California Gov. Pete Wilson, who has since quit the race.

A few moments later, Buchanan criticized a Dole campaign ad that calls Buchanan ``extreme.'' Buchanan turned to Dole and asked ``If I'm extremist, why are you pirating my ideas and parroting my rhetoric?''

When the candidates were asked to defend their advertising, Dole said he was under a negative assault from Forbes more than three months before responding. ``We've got a right to defend ourselves,'' he said. To lighten things up, Dole jokingly complained that Forbes was using an unflattering picture in his ads and turned to his rival and passed him a new photograph.

Buchanan, the surprise of the race after a win in Louisiana's caucuses and a close second to Dole in Iowa, promised voters a president who aggressively opposes abortion and takes on ``big transnational corporations'' that are sending American jobs overseas.