Vice President Gore today launched his harshest attack to date on former senator Bill Bradley, ridiculing his rival's health care plan as a big, but bad, idea that would ravage many vital domestic programs and block new initiatives.

The blast came on the day after Gore and Bradley participated in a generally civil town hall meeting in New Hampshire. Energized by what aides said was a strong performance in the Wednesday night event, Gore seized on one of their few areas of difference in an effort to find an opening in his tight race for the Democratic presidential nomination.

"It may be a big idea, but it's not a good idea," Gore said, mocking Bradley's trademark "big ideas" slogan. "Alchemy was a big idea, but it wasn't a good idea; the 'Contract With America' was a big idea, but it wasn't a good idea; supply-side economics was a big idea, but it wasn't a good one."

The health care debate was by far the sharpest disagreement to emerge from Wednesday's town meeting at Dartmouth College. Democrats and Republicans both said today the question about how much Bradley's plan would cost represented potential trouble for him.

"In the long run, I think it's going to be an important issue, and if it's not an issue for the Democrats, it will be an issue for the Republicans in November [2000] if Bradley gets nominated," said William Mayer, a political science professor at Northeastern University. "It's a proposal that Bradley will need to defend a lot more than he did last night."

Campaigning in New Hampshire, Bradley defended the fiscal estimates of his plan: "I strongly disagree that our program costs anything near what he says." But stung by the attack, Bradley's campaign issued a document asserting that the cost estimates, according to its experts, were based on "sound and reasonable assumptions."

Bradley spokesman Eric Hauser said Gore's harsh rhetoric proved that the vice president prefers attack politics to genuine discussion. "Despite a 24-hour pause [for the forum], it's pretty clear that attacking is a staple of the campaign and that's what they're back to," he said.

The Wednesday forum marked the first joint exchange between the two Democratic rivals. While few analysts in either party regarded the event as a defining moment in the race, which has become increasingly competitive, they said it revealed clear differences in style between Gore and Bradley that could prove important in coming months.

Most of those who said they had seen the hour-long session gave Bradley high marks for his performance. The assessments of Gore were more mixed, with some Democrats saying he showed clear improvement as a candidate and others worrying that he had been "over-coached" to appear natural.

Today, it was back to business in the Gore campaign, with the candidate focused on undermining Bradley's candidacy by challenging the domestic centerpiece of his campaign, a $65 billion-a-year plan to dramatically expand health care coverage.

Armed with a new study by former Clinton administration health analyst Ken Thorpe, Gore, as he had the night before, accused Bradley of advancing a plan that would cost $1.2 trillion over 10 years, not $650 billion. That, he said, would devour the projected $1 trillion surplus and leave no money for new initiatives. "Senator Bradley's plan definitely puts the future of Medicare at risk," Gore said.

Gore also accused Republican front-runner George W. Bush of financial foolishness with his endorsement of a $762 billion GOP tax cut bill. "Both the Bradley campaign and the Bush campaign have had serious problems with fiscal responsibility," Gore said today as he campaigned along the Mississippi River. "In both cases they are poised to sacrifice fiscal responsibility and along with it the strong economy."

Bradley's team spurred into action today, producing its own collection of experts to defend the former senator's approach as both visionary and fiscally responsible.

"Fundamentally, the Bradley plan is more expensive," said David Cutler, an economics professor at Harvard University who has advised Bradley. "They represent different philosophies; Bradley has a broad-based subsidy to encourage families to buy insurance while Gore tries to pick off specific target groups."

Gore repeatedly framed the health care debate around Medicare, the government program that provides coverage to the elderly and disabled, and historically a potent political weapon. "Medicare is a huge issue," Gore replied when asked why he was focusing on Bradley's health plan. "Most people assume serious campaigns will treat it with care."

Bradley aides said he not only wants to preserve Medicare but also supports adding a prescription drug benefit, as does Gore. "The Gore campaign doesn't have any credibility to analyze anybody else's programs when they've done so little to put a price tag on anything they're proposing," Hauser said.

Some of those who watched said both candidates had accomplished much of what they had hoped.

"We had a good taste of Bradley's laid-back style and his more visionary--and sometimes eloquent--message versus Gore's vast array of knowledge and strong sense of what the government does and what's going on and what needs to be done," said Bill Carrick, a California-based Democratic strategist.

Carrick described Gore as "vastly improved" as a candidate but said he had been "over-coached" by aides offering advice on how to seem more personable and human, from distancing himself from Clinton to asking personal questions about members of the audience.

Brian Lunde, a Democratic strategist, said, "I think you have to give the edge to Bradley. When candidates agree on most issues, voters look to personality and style and that's where Bradley probably has the advantage. After Clinton, bland is beautiful."

Greg Mueller, a top adviser to GOP candidate Steve Forbes, said: "I actually thought Gore was better stylistically and think he accomplished what he needed to accomplish. He needed to distance himself from Clinton but take credit for some of the good things going on. But on substance, I thought Bradley really had his proposals down."

Both Gore and Bradley offered expansive views of using the federal government to solve problems. "It seemed like it was a throwback to the old, traditional liberal Democratic Party," said Steve Duprey, New Hampshire Republican Party chairman.

Republican pollster Robert Teeter said the forum was evidence for why Democrats may come to regret the nomination fight that has developed this fall. "It is the absolute proof why primaries are bad and contested nominations are bad for people," he said. "They spent all the time talking about the left end. The amount of time spent talking about what the country thinks about was very small."

Connolly reported from Iowa, Balz from New Hampshire.