Dickerson: Joe Biden brings emotion into the debate, hammering Paul Ryan, Mitt Romney

In the vice-presidential debate, Joe Biden found a way to be both a participant and the guy in the Barcalounger at home yelling at the television.

He interrupted Paul Ryan, moderator Martha Raddatz, and even himself with interjections, sighs and quips. He appealed to the heavens, he looked to the floor. With all the activity, he surely shed calories. When he wasn't engaged in those antics, Biden laughed and smiled to himself as if Ryan had sold him something illegal that he'd just consumed.

At times his treatment was so dismissive, he seemed only a few threads of restraint from reaching across the table and patting Ryan on the head.

Biden won the debate, but it was a qualified victory.

He energized Democrats who had been down in the dumps since the president’s supine performance, but he also energized Republicans who found him rude and dishonest. Swing voters might have been turned off, too. But it probably doesn’t matter since they’re going to vote for the top of the ticket. It was close in the post-debate polls of undecided voters. It was close in the post-debate polls.

In a CBS poll of undecided voters, 50 percent thought Biden had won; only 31 percent thought the same of Ryan. In the CNN poll, 48 percent thought Ryan won. Only 44 percent thought Biden came out on top.

There's an old line attributed to Bill Clinton: It's hard for the other guy to talk when your fist is in his mouth. Biden was up to his elbow. That thrilled Democrats. Speaking of himself, Barack Obama said that he was "too polite" in the first debate. No one will say that of Joe Biden.

Biden's performance was aimed at one thing: painting the Romney and Ryan agenda as a flim-flam operation. He did it with style as much as substance.

Looking directly at the camera, he said, "folks, follow your instincts," in the middle of an argument about whether Romney's tax plan added up.

Before the debate, a Romney staffer had said one of the things that had worked well for the GOP nominee a week ago was that while voters may not have understood his policy ideas, he sounded like he understood them, which gave viewers confidence in the candidate. Biden was trying to make the same kind of transference. If he could convey exasperation and frustration with Ryan's lack of specificity, the plans that didn't add up, and the broader claims from the Republican team, perhaps he'd be able to make people doubt the entire Republican enterprise.

Biden hit the thesaurus hard. He blurted out that Ryan was offering "malarkey." At one point, he referred to a Ryan riff as "a bunch of stuff." He called out a "bizarre statement" and several times talked about "loose talk" and "slipshod" claims.

(What? No hokum?) The audience for the Biden routine was the middle class.

As expected, Biden brought up the secretly recorded video tape in which Romney wrote off 47 percent of the country as dependents and moochers. "These people are my mom and dad - the people I grew up with, my neighbors," said Biden, at the start of an extended riff defending everyday middle-class Americans.

Ryan responded with his own number, 10 percent, which is the unemployment rate in Scranton, Pa. He then blew that fact into a more extended argument about the lousy Obama economy. That argument then pivoted to a defense of Romney, which included a great story about how the Republican nominee paid the college bills of a man in his church whose children had been paralyzed in a car crash. The exchange was like much of the debate: Biden was defending the middle class, while Ryan was defending Romney.

Biden hammered Ryan's plan to change Medicare and pointed out that the next president would appoint justices to the Supreme Court that could limit abortion rights. On international affairs, though Biden floundered on Libya, he pressed Ryan on Iraq and Afghanistan, questioning effectively whether the logical conclusion of Romney's aggressive stance toward Iran and Afghanistan meant a deeper military commitment to conflict. "The last thing we need is another war," said Biden.

Biden's greatest asset was his passion. Though he might have been over the top, it was possible for a viewer to conclude that he was simply passionate about the middle class. That is something President Obama will not easily duplicate if he hopes to use Biden's performance as a teaching tool for his outing next week. Biden looked like he wanted to be there. Obama will have to find a way to access some measure of that emotion.

Emotion doesn't work for all things.

Indeed, the debate began with a question about the attack on American diplomats in Libya, where the administration is losing credibility by the news cycle.

The Ryan team knew the Libya question would be asked first. They had prepared to make an over-arching claim about Obama's penchant for blaming others. This week, a senior official in the Obama campaign suggested that the Libya issue had become politicized because Romney and Ryan had pushed it. "They first blamed the YouTube video. Now they're trying to blame the Romney-Ryan ticket for making this an issue," said Ryan.

The goal was to make a larger claim: that Obama has run out of ideas, so he and his team are only able to offer excuses. Ryan's execution wasn't great, but things are not going so well in Obama-land that all the smirking and cockiness are warranted. As the economy improves (or people start to think it's improving), the Romney camp may need to rely on a broader argument about Obama's incompetence.

Biden tried to turn Ryan into Dan Quayle. Ryan didn't fit the mold. He had done his homework and held his own, defending his Medicare plans and insisting that the economic growth created by reducing tax rates would allow Romney to keep his budget promises. Republicans won't be depressed the way Democrats were after Obama's weak performance. Ryan did not give a particularly fabulous articulation of the Romney plan for the middle class, but that's the candidate's job. (Neither man talked much about plans for the future - except in the context of defending their plans against the other man's attacks.) Ryan also did not answer questions about specifics, which is an issue that still dogs the campaign.

The worst moment for Ryan was when he had to own up to the two letters he wrote asking for stimulus funds. Biden painted Ryan as a phony, railing against the stimulus on the one hand and asking for money on the other. This is the larger Obama narrative on Romney-Ryan. But Biden calling Ryan out as a stimulus hypocrite didn't feel like a moment that people will remember. (It would have helped if he had the letters, but the debate rules forbid any visual aids.)

If the Obama camp can ever find an example that sticks, it will reinforce their broad claim against Romney and his running mate.

Biden's performance was good for the home team, but spectators won't be talking about it days from now. He didn't mint a line that will live on, but Democrats didn't need that. They know all the lines. They just wanted to hear someone from their team say them.

Dickerson is Slate's chief political correspondent.