Four years ago, Joe Biden was an afterthought: All eyes and ears were on the Sage of Wasilla. Tonight, he dominated. I have no idea what most Americans thought about tonight’s debate, but I’m fairly confident about what determines their opinions: Anyone who likes Joe Biden almost certainly thought he totally crushed Rep. Paul Ryan (R-Wis.), and anyone who didn’t like him before the debate almost certainly thought he was an overaggressive, boorish goofball.

From the opening — “Malarkey!” — onward, especially in the first half, the vice president maintained a contemptuous attitude toward “his friend” Ryan (you can take the man out of the Senate . . . ). That included at least half a dozen ways of calling what Ryan was saying nonsense; it included Biden’s trademark wild facial expressions, including at times openly laughing at Ryan; and it included constantly interrupting Ryan. That wasn’t all that Biden had going on: He showed the advantages of experience in the format, doing a great job of switching between answering the moderator to looking straight into the camera and talking to voters. And he showed the middle-class spirit that had big-name Democratic consultants falling all over each other to work for his misbegotten 1988 presidential run, slamming Mitt Romney and Ryan on taxes, on “47 percent,” on the auto bailouts and more.

It was, compared with last week’s tame affair, much better television. Did it “work”? That entirely depends on the goal. If it was to change minds, no, that seems unlikely. If it was to re-invigorate Democrats who were despondent over Romney’s recent polling surge, or those who were angry with the president for a flat performance last week, then it probably did what it was meant to do.

Ryan? Yeah, he was there, too. For the most part, his performance was fine, although he did get seriously off track more than once — particularly when he was baited into defending Social Security privatization (something that Ryan has pushed hard for in the past, but Romney isn’t running on), and when he somehow managed on Afghanistan to argue in favor of putting more American troops in the most dangerous places. For the rest of it, though, Ryan basically hit his talking points. His real problem was that he just had no answer to Biden’s disdain. 

I should say at least a word or two about substance. Romney — and Ryan — continue to have no answer at all to the charge that their tax plan doesn’t add up. They continue to cite “six studies,” but that answer has been shown to be a farce — it’s not six studies (more like a couple of studies, an op-ed and a blog post) — and, at any rate, none of them say that Romney can cut taxes 20 percent and maintain the other tax treatments that Romney has committed to unless he either raises taxes on the middle class or increases the deficit. Nor do Romney-Ryan claim that they can’t release any details about specific spending cuts they want or any tax expenditures they would curtail, because somehow that would violate leadership and bipartisanship pass-the-giggle test. On other issues, Biden was able to effectively use Ryan’s past extreme positions against him, batting back criticism of the Libya attack by pointing out that Ryan had voted to cut diplomatic security.

I thought the most fascinating attack was Ryan’s line, repeated three times, by my count, about the “unraveling of the Obama foreign policy.” The problem? It seemed to be entirely substance-free. Unraveling how? Where? Nothing. Just “unraveling.” It is, like most Republican attacks these days, a devastating line if you axiomatically assume that Barack Obama has been a disaster in office. If you don’t — and on foreign policy, most people don’t — it’s hard to believe that it does Romney any good. On the other hand, probably better to be vague than to fill in a policy and get into trouble.

Bottom line: It was probably a night that put Democrats, especially those dedicated enough to watch, in a much better mood than they had been for the last week. It’s possible that might even move the needle a bit by pushing them to answer pollsters with a bit more enthusiasm. But soon enough, the nominees will be back onstage, and if Obama wants to keep any gains with Democrats that Biden may have made tonight, he’s going to have to do it himself.