Nuclear Power Injects a Spark in N.H. Debate : Democrats: Four rivals attack Tsongas’ support of this energy source in last such forum before the primary.

In their last joint appearance before Tuesday’s high-stakes New Hampshire primary, the five major Democratic presidential candidates Sunday coasted through a generally desultory debate enlivened only by attacks on former Massachusetts Sen. Paul E. Tsongas for his support of nuclear power.

Tsongas, who leads in state polls, repeatedly came under attack for his staunch backing of nuclear power--a controversial position in a state where many Democratic activists have long opposed the Seabrook nuclear power plant. Each of Tsongas’ four rivals said they would decrease the nation’s reliance on nuclear energy.

“We’re not all trying to gang up on you, we’re not trying to say you’re wrong all the time,” Nebraska Sen. Bob Kerrey said to Tsongas at one point. “But on this particular issue I think you are. . . . Nuclear power, it seems to me, is fatally flawed.”

The focus on nuclear power--an issue that until recently has played virtually no role in the campaign--underlined the shift in Tsongas’ position from a long-shot who had been gently patronized to a front-runner worthy of pummeling. But other than the criticism of his energy policy--an issue that has not been high on the list of voter concerns here in recent years--Tsongas ran this last gantlet before the vote virtually unscathed.

Early in the debate, former California Gov. Edmund G. (Jerry) Brown Jr.--who later grilled Tsongas most aggressively on his support for nuclear power--even embraced him as a fellow outsider committed to “the politics of the future” as compared to the three current officeholders in the race.

Brown then mildly distanced himself from Tsongas, saying the former senator “represents a more conservative, business-oriented view of the future.”

In fact, the tone of the debate was strikingly low-key, with all of the candidates focusing more of their fire on President Bush than their rivals. Tsongas took the lead, employing the front-runner strategy used earlier by Arkansas Gov. Bill Clinton. At every opportunity Tsongas stressed his agreements with his rivals and his differences with Bush.

In the debate, sponsored by Cable News Network and the League of Women Voters, the candidates were hampered by a format so disjointed and at times unstructured that twice Clinton felt compelled to suggest questions to moderator Bernard Shaw.

After weeks of focusing on the bread-and-butter concerns of voters in this economically ravaged state, the candidates Sunday found themselves exploring international population control, the destruction of the rain forests, utility pricing reform and whether the nation needs a better class of light bulb.

In this alternately esoteric and disengaged atmosphere, the only energy was generated by the issue of nuclear power.

One by one, each of Tsongas’ rivals insisted they would reduce reliance on nuclear power. Harkin declared that a program “of developing solar . . . for the future” would allow the nation to avoid “going to the nuclear option that Paul Tsongas wants to move to.”

Brown said he would move to phase out all nuclear power plants over the next decade.

Clinton said: “I do not favor anything that will accelerate the building of nuclear power plants. If you have major incentives to the utilities to engage in conservation, if you have a major attempt to convert to natural gas wherever you can. . . . I do not think you are going to see a need for new nuclear power plants.”

Tsongas--after characterizing nuclear power as part of “the third tier” of his preferred energy options for the country--argued in response to the persistent jabs that a reduction in reliance on nuclear power would require greater use of fossil fuels, raising the threat of global warming through the greenhouse effect.

“If you take out all of your nuclear power plants by definition, you are going to have more fossil fuel burning and add to the greenhouse effect,” Tsongas said. “I take the position that the threat long term is global warming.”

Though Tsongas forcefully held his ground, he bristled under the attacks--which were among the most pointed he has endured. “If I could, I would like . . . to characterize my positions myself and not have others do it,” he said.

After the debate, aides to the other candidates maintained that Tsongas had been weakened by the focus on an issue. “I don’t think his position has been laid out before as it was here tonight, so I think it will hurt him,” said Frank Greer, Clinton’s media adviser.

Thaleia Schlesinger, Tsongas’ sister, countered: “People understand his position was based on his fear of global warming.”

When not arguing over whether to split atoms for energy, the candidates managed to make some points about the economy. To a greater degree than usual, Tsongas declared that his approach--which relies heavily on increasing capital incentives for business and rejects a tax cut for the middle class--offered struggle as well as reward.

“There are two roads,” he said in closing remarks. “One is easy, one is comfortable, but it is downhill. The other is the road to economic prosperity. . . . That road is steeper and it’s harder, but it’s more noble and it’s more worthy.”

Harkin reiterated his support for cutting the defense budget in half over 10 years to support infrastructure investments and other programs at home. And he took a harsh line on trade issues, promising to stand up to Japan and prevent former government trade negotiators from lobbying for foreign governments. “I’m saying trade has to be a two-way street, not a one-way bridge,” he said.

As he has in recent days, Clinton sought to differentiate himself from Tsongas by emphasizing his experience as chief executive in Arkansas and his plans to reform government. “I think we have to have a more activist government,” he said, “but it also has to be more community-based, less bureaucratic and provide more citizen choice.”

Like Harkin, Kerrey insisted that America needed to get tougher with Japan on trade. But he called for the establishment of “new trading structures so that we can expand trade into the rest of the world, trying to convert . . . old enemies into new customers.”

Tsongas, who has taken the strongest free-trade position, urged voluntary protectionism, saying that as President he would ask Americans to shun Japanese imports if Japan doesn’t open its markets. “If the Japanese are not willing to be reasonable,” he said, “you have to play hardball.”

For most of this encounter, though, hardball was apparently the last thing on the minds of the five Democrats chasing the White House. With Tuesday’s pivotal vote in sight, they seemed less like contenders stepping into the ring than weary fighters embracing at the end of a bruising match.

Times political writer Robert Shogan contributed to this story.