WASHINGTON -- After watching a videotape of Monica Lewinsky's deposition, Sen. Orrin Hatch, R-Utah, says testimony by her in the Senate could sway many Americans against President Clinton.

But he expects the testimony will not be allowed -- and even doubts whether Clinton opponents have enough votes to allow portions of the videotaped deposition to be played publicly."She's young, vulnerable and credible," Hatch said after watching the video, as reporters swarmed the Senate Judiciary Committee chairman for comment.

"I was impressed with her as a witness," he added later. He also said that the closed-door deposition proved that putting her on the stand "would not be a spectacle. She was very composed and very credible."

He said he is also convinced that Senate testimony would not need to delve into salacious details of her affair with Clinton but would focus more on possible obstruction of justice and perjury. "I think it could be handled in a very dignified way."

Hatch, a former trial lawyer, said he learned long ago that witness testimony "is critical in most cases," especially when "deciding morals or fact differences."

He said, "I think it (testimony by Lewinsky) would change some people's minds. There is a real difference between just reading a transcript and hearing what someone says and watching how they say it."

Hatch said that is one reason the Senate should not put too much weight on polls that say the public wants the trial to end now. "None of them have seen Monica Lewinsky testify, so I'm not sure you can rely on the polls."

But even Hatch conceded, "I don't think the votes are there to allow live witnesses, but I think it would be helpful."

He also lamented, "If we don't have witnesses, this would be the first impeachment trial ever . . . where we don't. Others have averaged 25 witnesses each, and each witness took about a third of a day. We are down here to just three witnesses."

Sen. Bob Bennett, R-Utah, also predicted that testimony by Lewinsky in the Senate is unlikely. His press secretary, Mary Jane Collipriest, said the video showed him that Lewinsky "is a poised, smart young woman. But viewing the deposition didn't bring any new information for him. So he does not expect her to be called."