DOLE BACKERS VOICE DOUBTS ON CANDIDACY.

Byline: Richard L. Berke The New York Times

Leading supporters of Sen. Bob Dole on Thursday portrayed his campaign as faltering, and said they feared he could no longer count on New Hampshire as an inevitable stepping stone toward the Republican presidential nomination.

In a series of interviews, many of Dole's most outspoken advocates - and even some of his top aides - said that his commanding lead had slipped dramatically against Steve Forbes in the last several days, particularly in this state, which holds the nation's first primary in less than three weeks.

While it is common for candidates to try to lower expectations over the outcome of a coming primary, Dole's own campaign staff officially remained bullish about his prospects and discounted accounts of his problems. But other Dole associates, speaking both publicly and privately, said that while they had expected the race to tighten, they were not prepared for Forbes, the publishing magnate, to emerge so quickly as such a formidable competitor.

"This campaign is thoroughly volatile right now - it's cracking wide open," said Ruth Griffin of Portsmouth, a local office holder, veteran Republican operative and strong backer of Dole. "I'm telling you there are a lot of people who are out there changing their minds."

John Stabile, the state Republican chairman who is remaining neutral, said "there is a horse race here," adding pointedly: "It's a wake-up call for Dole. Let's see if he wakes up."

Former Sen. Warren B. Rudman of New Hampshire, one of Dole's closest advisers, praised the senator's toughness and said he would ultimately prevail. But he, too, seemed stunned at how well Forbes was doing.

"It's like someone comes and spends a billion dollars on a new toothpaste that wipes out the competition, even though it tastes terrible," Rudman said.

Many Republicans, including Rudman, said they were worried that Dole's troubles were not necessarily caused by Forbes but by the majority leader's failure to energize voters. "It's hard for anyone who's been in public life as long as Bob Dole to inspire much passion, frankly," Rudman said.

Even William B. Lacy, the deputy campaign manager, said Forbes is doing far better than the campaign expected and is causing voters to move from the senator to the undecided column. "It's a real change in terms of the dynamics of the campaign," he said. "Our critical strategic task over the next few days is to remind people why they were for Bob Dole from the beginning."

Reacting to Forbes' strength, Gov. Stephen Merrill of New Hampshire said he would assume a far more active role in campaigning for Dole. His help is reminiscent of the way then-Gov. John H. Sununu succeeded in resuscitating George Bush's candidacy here in 1988.

And the Dole campaign is making an all-out assault on Forbes' signature flat tax as harmful to middle-class voters. In a commercial the Dole campaign began broadcasting Thursday, Merrill warns: "Steve Forbes' income tax plan increases the deficit and raises our taxes."

The latest evidence of Dole's troubles is a poll of 400 likely Republican primary voters published Thursday in the Boston Globe that shows that Forbes has caught up and perhaps overtaken Dole in New Hampshire. Forbes has 31 percent, followed by 22 percent for Dole. The other candidates were in single digits. The poll, conducted Jan. 29 and 30 by KRC Communications Research for the Globe and WBZ TV, has a margin of sampling error of plus or minus 5 percentage points.

Campaigning at an automobile dealership here Thursday, Dole dismissed the poll, saying, "If I worried about every poll, I'd probably have an Excedrin headache. They're coming so fast now that you get poll fever."