DEBATE DELIVERS DEFINING MOMENT FOR UNDERDOG DOLE.

Byline: Dick Polman Knight-Ridder Tribune News Wire

The curtain will rise tonight on the final act of the 1996 presidential campaign. The two major candidates will face off in the first of two debates, matching wits for 90 minutes in roughly 40 million homes.

And for underdog Bob Dole, the challenge is clear: Somehow, some way, he must blow the president of the United States right off the stage.

``Dole has to look at this debate as his last, best chance to turn this election around,'' said an expert on presidential debates, David Birdsell of Baruch College in New York. ``This is his last programmed opportunity. He can't hope that some combination of Saddam Hussein and a West Bank crisis will turn people against Clinton. He has got to do it himself.''

Can Dole erase public skepticism toward his tax-slashing plan? Can he attack Bill Clinton as a waffler or a closet liberal without alienating viewers? Can he sell people on the notion that, in his words, the American economy is really ``in the tank''?

Many question whether Dole can neutralize Clinton in a forum that seems well-suited to the president's telegenic prowess. Forensic skills often don't matter in these encounters.

Even Dole's handlers are less than thrilled. Said one key campaign official: ``We never wanted to be in a position where the debates would have to be the defining moment for us. But because of where the polls are and where the calendar is, now the debates are extremely important.

``We've got to massively change a lot of minds. Unfortunately, public opinion is starting to freeze.''

That may prove to be Dole's biggest hurdle, regardless of what happens in the debate. Pollster Andrew Kohut, who directs the nonpartisan Pew Research Center, in Washington, finds less public interest in these debates than in those of 1992 or 1988. In a new survey, only 43 percent say they are ``very likely'' to watch, compared with 67 percent four years ago. In addition, by a 2-1 ratio, most who plan to watch have already made up their minds.

``This is a lot like 1984,'' Kohut said, referring to the year when Ronald Reagan trounced Walter Mondale. ``Most viewers will be looking for confirmation of what they already believe, not fresh revelations.''

David Tell, who worked as an anti-Clinton operative in the 1992 campaign, said: ``For this debate to really change the race, Clinton's head will have to rotate a full 360 degrees . . . or an alien being will have to come out of his belly. Because Bob Dole, on his own, has very little to say - and because the economy is strong, and the country is at peace.''

Actually, incumbents often stumble in debates - as in 1976, when Gerald Ford declared that Poland was not under Soviet domination, and in 1980, when Jimmy Carter quoted his young daughter on nuclear issues, and in 1992, when George Bush glanced at his watch and failed to connect with a forum of citizens.

Those incumbents went on to lose their races.

But none of the three went into a debate with Clinton's overwhelming lead in the polls. Said William Ballenger, a former Michigan GOP official who writes a political newsletter: ``In this debate, all he (Clinton) has to do is be statesmanlike, and he'll do everything he can not to antagonize Dole. He doesn't want to look like he's beating up on an old man.''

A top Democratic strategist said: ``If nothing new happens in the first debate, Clinton is in good shape. For Clinton, this is not about scoring points. This is not about having any surprises. The burden is all on Dole.''

At the same time, Clinton is likely to skewer Dole for his Senate votes - against the creation of Medicare in 1965 and, more recently, against gun control, the minimum-wage increase and family medical leave.

In theory, the debate could spark a lofty discussion about the proper role of government. But what happens tonight is probably less important than what is perceived Monday morning. Each side will put its best spin on the event and try to push that message on the stump, in the news columns and in the TV ads. So tonight Dole will seek a ``defining moment,'' a sound bite that puts Clinton in a bad light.

Dole's partisans, frustrated by long months of bad news, are thirsting for such a moment. They yearn for Dole to go on the attack, to play on Clinton's credibility problems.

``Clinton has been totally deceitful, and he has been allowed to get away with it,'' said Florida Republican chairman Tom Slade, whose state has been hit by a barrage of Clinton ads alleging that Dole and the GOP want to gut Medicare. ``Bob Dole has got to call him on the carpet about that.''

Whit Ayres, a Republican pollster based in Georgia, said: ``He has to make the character message compelling, and that hasn't happened yet. He needs to bring up things like the FBI files and ask how that personal material ended up in the White House. He needs to talk now about Whitewater.''

Indeed, Democrats are bracing for an assault designed to make Clinton blow his top. A Democratic strategist said: ``The question for us is: What will Dole do to surprise Clinton? What are the negative nuggets that he hasn't used yet?''

He suggested one possibility: In a recent PBS interview, Clinton hinted that he might grant pardons to those convicted in the Whitewater scandal. Democrats say that Dole could raise that subject or that moderator Jim Lehrer might. Lehrer was the interviewer on PBS.

Then there's the FBI memo that accuses Clinton of being soft on drugs. It was written 18 months ago, and Clinton has declined to show it to Congress, citing executive privilege. Some GOP partisans believe that Dole can use this in the debate to paint Clinton as both deceitful and liberal.

But many warn that Dole risks a backlash. As a college professor, Birdsell cites Dole's experience in the vice presidential debate in 1976.

``A lot of people remember the comment he made about `Democrat wars.' It has taken Dole 20 years to live down the reputation of being a hatchet man in a debate setting,'' Birdsell said.