Washington (CNN) -- Vice President Joe Biden is a gaffe-prone avuncular type; Rep. Paul Ryan's is a wonky Gen-Xer. But both men will face the same challenge at their debate on Thursday: staying out of their own way. "Biden, the thing he does so well for someone his age is he has a lot of energy," said Melissa Wade, a debate professor at Emory University. "A lot of the way he messes up is he's so energetic, he gets wound up and he finds an inappropriate metaphor and runs with it." Ryan, she said, needs to have the same energy as Biden, "or it's not going to fly."
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VP Biden and candidate Ryan will have to tread carefully while defending top of ticket
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Biden's off-the-cuff remarks and Ryan's inside baseball approach are their Achilles heels
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Biden is an experienced debater, while Ryan is a congressional veteran and budget expert
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