MANCHESTER, N.H.--Despite conservative commnentator Patrick J. Buchanan's stunning upset victory here yesterday, both second-place finisher U.S. Sen. Robert J. Dole (R-Kan.) and third-place Lamar Alexander are vowing to press on with their campaigns.

New Hampshire's inability to establish a clear front-runner means the Republican party must struggle over the next several weeks to define its platform and unite GOP supporters in its quest to defeat President Clinton in November.

"What this shows is that this is a party with serious ruptures on the issues and with no clear leader," political consultant Dayton Duncan said.

Yesterday's results will have different impacts on the Alexander and Dole campaigns, political observers say.

Most pundits feel that Alexander has now established himself as a formidable contender, while Dole's campaign could be in serious trouble.

Much of Dole's loss was Alexander's gain, as moderate Republicans turned to the former Tennessee governor because of his middle-of-the-road views, reluctance to engage in negative ads, and his ability to articulate a clear vision of America.

During his celebration at the Inn at Amoskeag Falls, Alexander claimed victory despite his third place finish and urged Dole to step aside and let him and Buchanan fight it out for the future of the party.

"We have fresh conservative ideas," Alexander told the overflow crowd of 600. "Let's put those ideas up against Buchanan."

Throughout the race, Alexander has said a finish near the top of the pack would propel him onward--and secure much-needed federal campaign dollars.

Meanwhile, across the city at the Center of New Hampshire Holiday Inn, Dole campaign officials tried to salvage some respect from his disappointing second-place finish.

U.S. Sen. Judd Gregg (R-N.H.) told reporters that Alexander is not a legitimate contender, that Buchanan's support would not stretch beyond the state line and that Dole is the only candidate who represents Republican ideals.

"Dole came out of New Hampshire one of two candidates in the race," Gregg said. "Bob Dole is the only person with the credentials to take on Bill Clinton."

But Dole's inability to articulate a clear message and his failure to offer voters anything more than a promise of steady leadership proved to be his downfall here.

"Buchanan was able to stress easy issues and play on people's fears," said Hanover resident Ed Lord. "[Dole] has a theme, but he has to communicate it better."

Last night, Dole tried to portray Buchanan as someone who would split the Republican party into two. He also tried to entice both Buchanan and Alexander supporters to join his campaign.