Conventional political wisdom suggests it's the top of the ticket not a vice presidential contender that wins or loses votes in a presidential election.
But 2008 has been anything but a conventional election.
Since the late additions of the vice presidential candidates to their respective party tickets last month, anticipation of their first meeting on the debate stage has been mounting.
On Thursday night in St. Louis it will reach culmination: Democratic vice presidential candidate and Washington veteran Sen. Joe Biden squares off against his Republican counterpart, Alaska Gov. Sarah Palin, in their one-and-only debate of the election cycle.
One presidential debate and a weekend of analysis behind it, the political expectations game for the vice presidential matchup has begun in earnest. The Obama-Biden campaign is trying to set the expectations bar low for its candidate while building up the debate face of its rival.
"I think that if you go back and look at the debates that Gov. Palin's had as a candidate, she's very skilled and she'll be well-prepared. I know she's preparing this weekend," said David Axelrod, chief strategist for the Obama campaign. "As you saw at the convention, she can be very good, so I think it would be foolish to assume that this going isn't going to be a really challenging debate."
Axelrod contends that Biden isn't headed into the debate "to go after Gov. Palin" but rather "to make the case for Sen. Obama."
Biden spokesman David Wade played the expectations game to an even greater extreme, characterizing Palin as a formidable opponent.
"He's going in there to debate a leviathan of forensics, who has debated five times and she's undefeated in debates," Wade said.
Palin Rallies, Prepares, Debates
At a joint rally with Sen. John McCain in Columbus, Ohio, Monday, the Alaska governor praised her running ticket's Friday performance and promised the cheering crowd, "I'll do my part in St. Louis this week."
"I do look forward to Thursday night and debating Sen. Joe Biden," Palin said before mocking the Delaware senator's more than 30 years on Capitol Hill. "I'm looking forward to meeting him, too. I've never met him before. But, I've been hearing about his Senate speeches since I was in the second grade."
The hit on Biden's 36 years in the Senate was odd coming from the running mate of McCain, 72, a man who has been in Congress for the past 26 years and whose age has been cited as a concern of many voters, according to the latest ABC News/Washington Post poll.
The McCain campaign has been short on details regarding the specifics of Palin's preparation, though the Ohio rally was likely her last public appearance before heading to the Arizona senator's Sedona ranch, where she'll be joined by her husband, to spend Tuesday and Wednesday in intense preparation.
McCain's top adviser Steve Schmidt traveled to Sedona with Palin; McCain campaign manager Rick Davis worked with Palin in Philadelphia this weekend.
The team in Sedona is joined by by Mark Wallace, deputy campaign manager to President Bush in 2004, and former Bush NSC staffer Steve Biegun who has been working as Palin's lead foreign policy adviser.
Female Senators Advising Biden
Known for off-script moments and colorful remarks that can be interpreted as reckless and insensitive, Biden has been preparing for the Show-Me State showdown against the GOP's first woman vice presidential nominee with advice from a number of prominent female Democrats in the Senate, Barbara Boxer, Dianne Feinstein and Hillary Clinton among them.
"They asked me if I could handle Sarah Palin?" said Biden at a Sterling, Va., rally in mid-September. "I said try debating Barbara Mikulski."
Earlier in the month in Wisconsin, Biden acknowledged certain pitfalls in perception "if two people with different genders or different races or different ethnicities debate one another."
"You worry about, you may say something, either person may say something that comes off the wrong way," Biden said.
To help Biden prepare, Michigan Gov. Jennifer Granholm joined the Delaware senator in Wilmington, acting as the primary stand-in for Palin, for at least two days of debate prep that started Monday morning.
"I don't think anybody really looks forward to debate prep," said Wade. "It's kinda like looking forward to homework."
Still, part of the challenge for Biden in debating Palin is facing "someone who is largely unknown," as Obama campaign manager David Plouffe put it. Even Biden has stated that he does not know where Palin stands on major issues.
The McCain campaign has made the Alaska governor famously inaccessible to the press -- absent from the Sunday morning circuit, Palin gave her first press conference Sept. 25 at ground zero and has done sit-down interviews with ABC's Charles Gibson, Fox's Sean Hannity and CBS' Katie Couric.
Following her interview with Couric, Palin has encountered something of a backlash from a conservative blogosphere that once embraced her as it questions her credentials and ability to lead on issues of domestic and international policy.
Stephanopoulos said the degree of difficulty will be high for the Delaware senator as well. "It's always difficult in these debates, particularly for someone like Biden, not to appear too aggressive or too boorish, and he's got to be careful about that."
Part of Palin's strategy will be an aggressive attack on Obama as a liberal, McCain campaign officials told ABC News, putting him on the defensive so that Biden will have to answer for Obama.
Whatever tactics Palin employs, Biden remarked immediately following last Friday's debate between Obama and McCain that he hopes his Alaska opponent comes to Missouri echoing McCain's talking points.
"I hope that she makes the same arguments that John McCain made," Biden told Fox News' Chris Wallace.
"Are you going to have trouble not being condescending to her and pointing out that you've been to all these places and she hasn't?" Wallace asked the more experienced Biden, chairman of the Senate Foreign Relations committee.
"No, no, no, I'm not going to do what John did," replied Biden, hitting out McCain's treatment of Obama at their Ole Miss duel.
ABC News' Ron Claiborne, Kate Snow and Jake Tapper contributed to this report.