Of course, Biden can be prone to commit an unforced error from the podium, handing Republicans an opening.
Most recently, Biden told a Virginia crowd that included hundreds of African-Americans that Romney's plans for Wall Street would put them "back in chains."
In May, Biden said on a Sunday talk show that he was "absolutely comfortable" with same-sex married couples having the same rights as heterosexual married couples. That essentially forced Obama to move forward with his support of same-sex marriage. Biden later apologized to the president for going off-script.
Republican strategist Steve Schmidt, who managed GOP nominee John McCain's 2008 presidential campaign, said Biden was a "formidable politician" and an "effective campaigner" who could garner support among voters prized by both campaigns, including blue-collar workers and Catholics in states such as Pennsylvania and Ohio.
Schmidt warned that the hits on Biden actually could have an unintended consequence heading into to the vice presidential debate set for Oct. 11 in Danville, Ky.
"When you ridicule someone, you're lowering expectations to a point that makes it a lot harder for Paul Ryan to score points," Schmidt said. "There's a downside in that."
Associated Press writer Brian Bakst in Tampa, Fla., contributed to this report.
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