CHARLOTTE, N.C. -- His unscripted and off-color remarks have provided a wealth of material for late-night comedians and plenty of headaches for the Obama campaign, but Democrats believe that the benefits Joe Biden will bring to the presidential race's final stretch outweigh any liabilities.
When asked if they're worried that the vice president might become a drag on the ticket, a common response among Democratic officials gathered here this week has been to dispute the question's premise.
"You're the first person who's ever asked me that," said Maine delegate Emily Cain, who serves as the House minority leader in her home state. "It's not a concern I've heard raised by anyone."
Biden's assertion last month -- to a largely African-American crowd -- that Mitt Romney's plan for banking regulations would "put y'all back in chains" was the latest reminder of the vice president's capacity to upend the campaign's message discipline. That tendency can surface any time the cameras are rolling but the teleprompter is not.
But here in Charlotte, the possibility of Biden saying something over the next two months that would truly jeopardize the ticket's re-election doesn't seem to be a major source of anxiety.
"It's hard to say vice presidents are that much of a factor in these races," said Jerry Clark, a Democrat from Washington, D.C. "The top of the ticket has always been the most important."
As one of the most visible and influential vice presidents in U.S. history, Biden has followed in the footsteps of his predecessor Dick Cheney, becoming a key administration figure who engenders strong opinions from both sides of the aisle.
In a Pew Research Center/Washington Post survey released Wednesday, respondents were asked to use one word to describe Biden. Thirty-eight percent chose a negative term, while only 23 percent used a positive one, and 39 percent came up with a neutral response, according to Pew.
"Good" was the most frequently used word to describe him overall, but most of the negative terms offered qualify as indictments of his ability to do his job effectively.
"Idiot," "incompetent" and "clown" were the most common negative characterizations.
And in a focus group conducted in Tampa last week, only two of the 23 swing voters present said that they would vote for Biden if he were at the top of the ticket. By contrast, all but a couple hands in the room went up when asked the same question about Secretary of State Hillary Clinton.
In Joe Biden, Republicans see a clear asset to their portrayal of the Obama administration as bumbling.
"He is so prone to gaffes that on the one hand, you want to say, 'Just keep talking,' " said Utah Rep. Jason Chaffetz, a national Republican surrogate who has been camped out at the convention here. "On the other hand, you shudder at the idea that he would actually become the president. I can't imagine anybody going to the polls saying, 'Man, I just love that Joe Biden.'"
The vice president's overall favorability rating has been consistently underwater, but recent poll results are more nuanced.
In a CNN survey released on Tuesday, for instance, Biden's favorability among likely voters was measured as a near split decision: 46 percent positive and 47 percent negative.
Democratic insiders are emphatic that they still consider Biden a key component of the president's re-election hopes, noting that he has already headlined more than 100 campaign-related events in swing states and elsewhere around the country.
Said Obama campaign press secretary Ben LaBolt: "Vice President Biden has been pounding the pavement for months, taking Mitt Romney's extreme agenda head on and making the direct case as no one else can for why President Obama should be re-elected this November. He has a tremendous ability to connect with middle-class Americans across the country and is an invaluable asset to the campaign."
Biden has been particularly well received this year by core Democratic constituencies, including labor groups, the National Council of La Raza, and the NAACP.
When he takes the stage at the Time Warner Cable Center on Thursday night, Biden will attempt to drive home the ticket's core economic argument -- that they are the real advocates for the middle class in the race -- while portraying Romney as out of touch with, and incapable of relating to, average Americans.
Biden's remarks will come on the same night that President Obama delivers his acceptance speech. It's a one-two punch that marks a change from 2008. In Denver, the vice-presidential nominee was granted his own night as a headliner a day before Obama accepted the nomination before a capacity crowd at the Broncos' football stadium.
Republicans see this scheduling shift as confirmation that Democrats want to downplay Biden's visibility -- a charge the Obama campaign denies vigorously.
According to Democratic sources, the president and vice president made the decision together to have Biden speak on Thursday.
"It's not an accident that they're speaking on the same night," said an Obama campaign official, who noted that overall viewership on Wednesday night was expected to be down, since one major TV network aired the NFL's season opener instead of DNC coverage.
Bill Clinton, whom the Obama campaign is currently featuring in television ads, was designated the featured speaker on Wednesday, but that does not make Biden's role any less relevant, Democratic planners say.
"Not to discredit former President Clinton, but the campaign wanted eyes on the ticket" Thursday night, the Obama campaign official said.
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Scott Conroy is a National Political Reporter for RealClearPolitics and a contributor for CBS News..