Mrs Palin took part in a debate with Mr Halcro (left) in Alaska in 2006
Ask nearly anyone in Alaska, and they will tell you that Governor Sarah Palin is a great debater.
If anyone knows the challenge that lies ahead for Senator Joe Biden, it is Andrew Halcro, 44, who took part in a handful of debates with Mrs Palin during the 2006 race to be Alaska's governor.
"The one thing I found during the  debates was no matter how knowledgeable her opponents were on the issues, it didn't matter," Mr Halcro told BBC News.
"She has an amazing ability to turn a 45-second answer into a folksy story... she's never been forced to know the issues."
Mr Halcro said Mrs Palin's biggest strength was her ability to "fill the room with her presence".
Having studied at Harvard's Kennedy School of Government and Harvard Business School, in addition to being an Alaskan and a lawmaker, Mr Halcro came to the debates armed with a wealth of knowledge and statistics.
Mrs Palin even said Mr Halcro would make "the awesomest statistician", when asked during a debate to which position she would appoint Mr Halcro if elected governor.
Governor Sarah Palin has performed well in previous debates
Still, statistics were not enough to put even the smallest dent in Mrs Palin's rising popularity.
"There were many times the third candidate and I would walk off stage and shake our heads," Mr Halcro said. "It wasn't policy, it was populism."
Whatever it was, Mrs Palin beat her opponents, garnering 48% of the vote, while Democratic candidate Tony Knowles received 40% and independent Halcro received 9%.
"I don't think anyone could have beat her," Mr Halcro said. "It wasn't about how much she knew about the issues. People didn't care about her experience, they just thought, 'This is the drink of water we need'."
Mr Halcro, and many others from Mrs Palin's home state, will be watching to see whether she appears on stage this Thursday to similarly capture the hearts and votes of the rest of Americans in the "Lower 48" states.
I think she has more to lose now. Her ratio of importance to the Republican ticket was greater than Biden's to the Democratic ticket. She carries more weight, so there's the possibility for an equally large downside
Lecturer in Public Policy, Harvard's Kennedy School of Government
But Richard Parker, a lecturer in public policy at Harvard's Kennedy School of Government, said it might be tricky to transfer her immense success in Alaska on to the national stage.
"I think she plays to great advantage the small town hockey mom persona," Mr Parker said. "For Alaska that's terrific. But for states like Ohio and Pennsylvania, who are dealing with panic about the economy, who knows?"
Mr Parker said that at the height of Mrs Palin's popularity honeymoon a couple of weeks ago, it had been Mr Biden who had most needed to put on a strong performance.
But with the downturn of the economy, the public's dubious reaction to Mrs Palin's recent interviews, and some conservative columnists calling on her to withdraw from the ticket due to her inexperience, Mr Parker said more focus will be on Mrs Palin.
"I think she has more to lose now," Mr Parker said. "Her ratio of importance to the Republican ticket was greater than Biden's to the Democratic ticket. She carries more weight, so there's the possibility for an equally large downside."
Nearly 55 million viewers tuned into the first presidential debate last Friday, and with unusually intense focus on the vice-presidential candidates in this election, Mr Biden and Mrs Palin can expect to have a lot of eyes watching them.
Senator Joe Biden, an experienced debater, says he will focus on policy
Mr Halcro, a Republican still unsure who to vote for in November, said the key for Mr Biden was to focus on the policy issues and let the moderator ensure Mrs Palin answered the questions.
"He shouldn't be afraid to point out contradictions in a respectful manner," Mr Halcro said. "He needs to be congenial and not appear patronising or bully-like."
Barack Obama's chief strategist David Axelrod has praised Mrs Palin's debating skills, recognising it would be a challenging debate.
"I would imagine that Biden and his counsellors are going to keep it as low key as possible and hope the questions she's asked will do her more damage," Mr Parker said. "The last thing he can afford is a disaster."
Mrs Palin, on the other hand, has the challenge of maintaining her impressive debating record and proving to the rest of the world that her readiness to lead is not in doubt.
"Ten days ago, if you asked how important the vice-presidential debate would be, I would say intensely important because of Palin's attractiveness across party lines," Mr Parker said.
"But now with what is going on on Wall Street, I don't think that her inexperience is going to play well."
The BBC will be streaming the Biden-Palin debate live on its website from 0100 GMT on 3 October, with live running commentary and further analysis from our correspondents in St Louis and Washington.