John Edwards is in a win-win situation.

If the Democrats capture the White House, he becomes vice president.

If they lose, he is automatically installed as the front-runner for the Democratic presidential nomination in 2008, sharing top billing with U.S. Sen. Hillary Clinton of New York.

But first, the South Carolina native must demonstrate his wares in a televised debate tonight with Republican Vice President Dick Cheney.

Two of the biggest challenges for the 51-year-old from Seneca will be sitting next to Cheney and appearing presidential, and turning his boyish looks and lack of experience in government into a virtue.

Edwards has not yet completed a full term in the Senate and never held public office before then.

“His first challenge is to look like a potential president of the United States,” says Merle Black, a political science professor at Emory University in Atlanta.

College of Charleston analyst Bill Moore says, “He has to really show the public that he has experience, background and knowledge and that he has a thorough understanding of the issues.”

Edwards’ facility with language — honed from years arguing cases in the courtroom — could be his biggest asset, political analysts say.

“His skill as a trial lawyer should help in his ability to explain complex issues so that a middle-school person could understand it,” University of South Carolina professor Blease Graham says.

The 90-minute televised debate will be held at Case Western Reserve University in Cleveland. Both Edwards and Cheney are expected to use their lone debate to focus attention on the men at the top of their respective tickets.

For Edwards, it will be his first one-on-one, nationally televised debate.

Vice presidential debates historically have not been consequential in presidential contests, but analysts say the timing and personalities of this one could make it an exception.

For the Kerry/Edwards campaign, the vice presidential encounter represents an opportunity to build on the momentum growing out of last week’s first presidential debate, which most polls and pundits awarded to the Democrats.

The pressure is on Edwards to keep the momentum going.

“This is the only opportunity Edwards is going to have to advertise himself,” Black says. “If he does a good job and puts Cheney on the defensive, he will become a hero to a lot of Democrats.

“But if Cheney holds him at bay, Democrats will say Edwards doesn’t have the gravitas to be vice president” — much less president.

And Kerry will be criticized for “exercising poor judgment” in the selection of a running mate, Frances Marion University political scientist Neal Thigpen says.

Because Edwards is an articulate man who thinks quickly on his feet, Moore says, the expectations are high for a good performance.

Thigpen goes even further: Edwards wins the debate on glamour alone.

Cheney, 63, is a balding, gruff veteran of GOP administrations. Edwards is a well-coifed newcomer, trim and effusive.

Edwards’ principal aim is to validate his selection by Kerry and to reassure voters he has the seasoning and knowledge for the job. He is expected to shift the campaign toward domestic policy issues, where Democrats historically are stronger.

The day after, Edwards will dominate a day’s worth of headlines and television newscasts, giving him exposure he hasn’t yet had. The debate is expected to draw tens of millions of viewers.

Will it advance Edwards’ political career?

“Yeah, just being picked accomplished that,” Thigpen says. “He can’t lose.”