Vice President Biden was aggressive in taking on Paul Ryan in their debate Thursday in a way President Obama wasn't last week against Mitt Romney, but Biden's smile may have stolen some of his thunder.
The vice president, especially toward the beginning of the debate in Kentucky, could be seen grinning and laughing -- some have said smirking -- during Ryan's answers, as he prepared to dismiss Ryan's points as "impossible" and "malarkey."
After the debate Republicans were quick to pounce on Biden's poise, calling it inappropriate and disrespectful -- even "unhinged."
"You almost can’t blame Joe Biden for being so unhinged. It must be frustrating to debate when you have a record that is so hard to defend and not a single tangible plan for the second term besides tax hikes," a statement from the Republican National Committee said in drawing attention to notable tweets about Biden's mirth.
Shortly afterward, the party put out a video montage of Biden grinning and laughing.
Former Bush spokesman Ari Fleischer, for example, tweeted, "The contrast between cool Ryan and overbearing Biden really hurts Biden. Biden is too hot - not effective."
Even members of the media pounced.
"Biden's smile is out of control," NBC News' David Gregory tweeted.
And Larry Sabato, director of the University of Virginia Center for Politics, added: "SNL will have to devote entire show just to Biden's facial expressions."
But Democrats quickly shot down the criticism, casting it as evidence of Republican desperation.
"Twenty-nine days out and they have been peddling this crap, and they don't even have the guts to put their tax plan out. They deserve to be laughed at," Maryland Gov. Martin O'Malley said. "Biden knew the person he was up against is a very immature person who is not ready for this job."
And Obama campaign manager Jim Messina defended Biden, saying he's simply a "happy warrior" for the middle class.
It remains to be seen whether that aspect of Biden's performance will help him, hurt him or be of no concern to voters.
But Jenny Beth Martin of the Tea Party Patriots argued it was worse than just an off-hand smile.
"Our vice president has shown he is an abusive political bully who belittles, mocks, ridicules and laughs at his opponent, the moderator, the viewers and anyone who questions this administration's lack of leadership," Martin said. "Solutions require respect. These skills the vice president, and this administration, clearly lack."
Democratic strategist Joe Trippi, a Fox News contributor, said he thought Biden delivered a strong performance overall, but it was "diminished" by the "smirking."
“I don’t know about the likeability of that smirking … I found it condescending and overdone," Trippi said.