But Romney and his supporters have beat back those notions.
Regarding the debate, Romney told CNN's Wolf Blitzer in a Tuesday interview: "I think President Obama and I both had a good chance to describe our respective views as to how we'd do a better job. And I, frankly, think I benefited from the fact that rather than having people learn about me from ads prepared by my opposition, they got to actually hear what I would do from myself. And I think that helped me."
Meanwhile, some Republicans have turned the arrows toward the vice president. Two of them occupy a special place in Biden political lore.
Christine O'Donnell tried to unseat Biden in 2008 before she waged a widely watched 2010 Senate race in Delaware in which she famously declared, "I'm not a witch."
By the time of the general election, Obama had picked Biden as his running mate. As Biden ran for vice president he also ran for re-election to the Senate. Once Biden elevated to the White House, ending his 36-year Senate career, Kaufman was picked to fill out the rest of Biden's term.
O'Donnell hoped to debate Biden for their Senate race but he denied her the match up.
In a statement to CNN, O'Donnell claimed that Biden "represents everything that is wrong with politics in America today."
"America will see a clear contrast between Rep. Ryan and him in the debate, and I am confident that benevolent capitalism will win out over the Obama-Biden collectivism."
Another former opponent was equally biting.
Ray Clatworthy, a Delaware businessman, ran against Biden in 1996 and in a rematch in 2002. He is the last person to square off against Biden in a Senate debate.
Clatworthy, who supports Romney, recalled numerous debates with Biden over the two election cycles. He called them "somewhat frustrating."
"I mean, Joe's a glib guy. He's a smart guy. But he is what he has to be at the moment. He will say almost anything at a given time in order to be able to advance his cause."
Clatworthy did call Biden a disciplined debater. But it was not intended as a compliment.
"In that debate...I'm sure they will have him just as disciplined as he's ever been," Clatworthy said. "But you won't be seeing the real Joe Biden."
A senior Democratic strategist, who did not want to be identified, said, "Sounds like what a guy who lost races and lost debates would say."
Biden beat both O'Donnell and Clatworthy by wide margins, with notable shares of Delaware's Republican vote -- though many in the blue state are moderate.
Kaufman said that Biden has always attracted Republicans.
Referring to Biden's first Senate victory, Kaufman said, "If you look at the ticket in 1972 and look at the ticket at practically every race since then, he runs quite a bit better in Republican areas than many other Democrats. So it's always been a place where he's been able to convince people to vote for him."
The former chief of staff cited Biden's strong family values among his attributes that appeal to conservatives.
That could explain why the vice president is diving deeply into conservative strongholds in battleground states to help his ticket win.
In recent weeks, Biden has campaigned in places that did not swing toward Democrats in 2008 and could offer little chance of doing so this year. Within the span of a few weeks, the vice president visited Fort Myers in Florida's Lee County, Chesterfield in Virginia's Chesterfield County, Fairborn in Ohio's Greene County, and Zanesville in Ohio's Muskingum County, to name a few.
He's also made recent visits to places like Asheville in North Carolina's Buncombe County, Tamarac in Florida's Broward County and Ottumwa in Iowa's Wapello County -- counties won by the Democratic presidential ticket in 2008 and that offer a repeat chance of success.
When asked about the vice president's travels, especially to red areas, the campaign demurred.
"He is beloved where he goes because he's been speaking out forcefully on behalf of the president to move this country forward," the campaign official said. "He is the president's partner and No. 1 surrogate. So nothing makes him happier than going anywhere and everywhere the campaign deploys [him] -- anywhere and everywhere to continue to make the case for the president."
Political experts offer more frank assessments.