The meaning of Joe Biden's laugh
If Joe Biden's reaction was anything to go by, Paul Ryan should give up his day job and become a standup comedian.
Joe chuckled and chortled, silently shook his head with mirth, and laughed out loud.
President Obama sometimes says he fails because he can't fake emotions. Maybe Mr Biden can't either, but he had a good try, hamming up his disbelief.
Through his music hall amusement, Mr Biden was trying to signal incredulity. His none too subtle message: Paul Ryan's arguments are a joke, and he is laughably callow.
Some found this condescension unattractive and off-putting.
On the back foot
They say generals always fight the last war. Mr Biden's performance was certainly intended to make up for his boss's lacklustre, unresponsive and passive performance last week.
He was strong and aggressive, repeatedly interrupting. The Republicans are portraying that as "out of control".
That may suggest they know Mr Ryan was on the back foot. The reaction to this debate will be far more partisan than the verdicts on last week's presidential clash because there was no runaway victor.
Mr Biden probably cheered supporters and annoyed opponents. Mr Ryan will have done the same, but his calmer performance may have been more attractive to the undecided.
The vice-president's tactic was effective, even if some found it too strong to stomach. It neutered Mr Ryan's own pretty strong performance and repeatedly put him on the defensive, having to explain his position.
Sometimes he did so clearly, but at other times, particularly on what a Romney administration would do in Afghanistan and Syria, he didn't have an answer.
That is not his fault: the Romney campaign has a clear line of attack against Mr Obama's foreign policy, but as yet they have not worked out convincing policies for the future.
A poll of two
This debate was most certainly not a game changer. Afterwards, I spoke to a couple of guys tending a late-night bar (naturally I was there purely in the interest of research). Both had been swept along with the magical mood of 2008 and had voted for Mr Obama.
Both were uncertain how they would vote this year. And neither of them had seen the debate, because nerve-racking playoff baseball and a tight football game were on the TV at the same time.
One sounded as though he would probably vote for Mr Obama in the end, despite his disappointment. He didn't like Mr Romney.
The other said abortion was the biggest issue for his "pro-life" wife, but he wouldn't be swayed by just one issue. My guess is that he won't vote.
My sample of two has a 100% margin of error. But it did reinforce my belief that this election will come down to whether Democrats can turn out people who won't vote for Mr Romney, but who are no longer convinced by Mr Obama.
That means that next week's debate really matters, and Mr Obama has to pull off a performance that is at least as strong as his vice-president - with a lot less laughter.