MANCHESTER, N.H. — PAT BUCHANAN and Lamar Alexander are stumping with renewed vigor in New Hampshire in the wake of Iowa caucuses that both rattled and winnowed the field of Republican presidential contenders.
It is now up to the Granite State to be the great thresher: Iowa didn't settle the field but instead made New Hampshire - and perhaps several other states to follow - all the more important in determining who the GOP nominee will be.
New Hampshire will test in particular several themes that surfaced in Iowa: that Bob Dole is a vulnerable front-runner; that religious conservatives, who were crucial to Mr. Buchanan's support, remain a vital force within the Republican Party; and that voters are unswayed, if not repulsed, by negative advertising.
New Hampshire has a history of reversing the direction Iowa sets. Although Senator Dole finished well below the 37.4 percent he captured in 1988, Iowa failed to produce a single challenger. That task falls to the Granite State.
Steve Forbes, who spent $4 million slashing his opponents over the airwaves in Iowa but finished fourth, could rebound. Taxes matter in New Hampshire. His anti-Internal Revenue Service message resonates well here.
Buchanan captured 37 percent here four years ago against an incumbent president and is expected to do well again this year. Mr. Alexander is appealing to voters by claiming he is the only Republican able to beat President Clinton.
Sen. Phil Gramm has, in all probability, been knocked out of the race. His distant fifth-place finish, following on the heels of a damaging loss in Louisiana last week, make it unlikely he'll be able to rebound here.
But three others have the potential to be competitive against Dole, whose support remains tepid.
If New Hampshire fails to hand the nomination to Dole, experts say, a muddy picture could last well into March, when multistate primaries occur every Tuesday.
''It is entirely possible that we'll go into April with the race undecided,'' says John Pitney, a political scientist at the Claremont McKenna College in California. ''There is an absence of enthusiasm for Dole,'' and no clear challenger as yet.
The primary question is what will happen to Dole. The Kansas senator stumbled badly here the last two times he ran. This time around he has the backing of Gov. Steve Merrill, who is very popular, and members of the state's congressional delegation. But Dole's campaign efforts were bogged down for weeks by the budget stalemate in Washington, and his base is thin. If Alexander gets a boost from Iowa, he may erode Dole's support among moderate and pragmatic Republican voters.
''If people decide they don't like Dole,'' says former New Hampshire Gov. Hugh Gregg, ''Alexander is the place to go now. Dole's people better get off the couch.''
That augers well for Buchanan, who could reap the conservative harvest now that Mr. Gramm is faltering. Four years ago, the religious conservative bloc was too small to register, but it has grown in the intervening years. If Dole and Alexander split the moderate vote, a coalition of conservatives could put Buchanan on top next Tuesday.
''We've won the title, Mr. Conservative,'' says Peter Robbio, Buchanan's executive director here. ''We're within striking distance.''
Many, however, question whether Buchanan has the legs to run the full race. The candidate's economic program, which calls for tough tariffs against Japan and China as a means of forcing open their markets, runs against the grain of mainstream Republican doctrine. Further, many in the party remain wary of Buchanan's often strident views on social policy.
''The religious right is an important part of the Republican coalition,'' says Steve Merksamer, a GOP strategist in California. ''But Buchanan is not broad-based enough to put together a national coalition. His economic program will hurt him in the industrial states'' such as Ohio and Illinois, he says.
All of the candidates now claim Forbes has stumbled. That may be. Momentum is hard to build again once it's lost. But the media mogul has unlimited funds, and has always claimed that the Feb. 27 Arizona primary is more important to his success.
Ultimately, however, Alexander's third-place finish in Iowa could prove to be the start of something. If Buchanan beats Dole in New Hampshire, Alexander may be the one who gains down the road. Moderate states such as Colorado and Massachusetts vote on March 5. The so-called electability issue favors Alexander, says Floyd Ciruli, a Denver-based pollster.
''It's hard to imagine Pat Buchanan as a national candidate,'' he says. ''And there is no Forbes boomlet in Colorado. There is a sense that Dole is just going through the exercise, and is unlikely to beat Clinton. It would not be all that difficult a transition from Dole to Alexander.''
That, in fact, is what the former Tennessee governor's campaign is counting on. ''The exit polls in Iowa told the story,'' says William Cahill, Alexander's New Hampshire campaign director. ''People said they supported Lamar because he has the ability to beat Clinton.''
An Iowa bounce was critical for Alexander's ability to raise cash. The campaign says it has enough for a full fight in New Hampshire and is bankrolling for the Southern primaries. If he falters here, though, he could have trouble filling the tank come Super Tuesday on March 12.
MR. MERKSAMER, meanwhile, is confident Dole will win the nomination in the end. A senior adviser to the senator's campaign, he isn't worried about hitting some rough terrain. In fact, he says, it may be beneficial in the end.
''Bob Dole may be the only individual capable of uniting all the elements of the party,'' Merksamer says. ''Dole will win New Hampshire, but have to work very, very hard. These primaries serve to fine tune the candidate.''
Former Governor Gregg, for his part, is confident New Hampshire will continue its tradition of choosing the next candidate, and clarify the race.
''New Hampshire has always done the job,'' he says. ''New Hampshire will pick the nominee. We've still got six days to go.''