Mike Pence put on a reasonably strong debate performance this week - stronger, in key ways, than that of Tim Kaine.
But in so doing, Pence inadvertently revealed the fundamental weakness of his running-mate's whole candidacy.
This weakness is surmountable, and Donald Trump could still win.
But right now, it looks more likely that Trump won't surmount it - and once you get past the noise and spin enveloping yesterday's festivities, what you see is that fundamental weakness sitting right there in plain sight once again.
During the debate, by my count, Kaine reminded the national audience of Trump's attacks on Mexican immigrants no less than five times.
He revived Trump's attacks on a Mexican-American judge twice.
He criticised Trump's misogynistic quotes twice and quoted Trump's suggestion that women should be punished for abortions once.
He blasted Trump's birtherism three times, in one case flatly describing it as bigoted.
And he aired Trump's plans for mass deportations five times.
All of that, of course, was designed to remind everyone of Trump's sexism, bigotry, racist campaign, and cruel, pathologically abusive streak.
Kaine also revived Trump's displays of ignorance about international affairs and his quotes about nuclear weapons and Russian President Vladimir Putin to press the case that Trump is dangerously unhinged and unfit for the presidency.
It's been widely observed that Pence either refused to defend many of Trump's statements or simply pretended he hadn't said them. This is being widely analysed by Clinton supporters as proof that you can't defend the indefensible and by neutral observers as a sign that Pence didn't help Trump as much as he might have done.
But I think this gets at something else that's important: it shows, in a roundabout way, how and why Trump may be currently on track to losing the election.
Top Democratic strategists have concluded that at this point, there are very few undecided voters left, based on both public polls and on private polling that attempts to push undecided voters to make a choice. This is the prism through which they are viewing yesterday's performance. As Jefrey Pollock, a pollster for the pro-Clinton Super PAC Priorities USA, emailed me today:
"'I would bet that there were very few truly undecided voters watching the VP debate last night, partially because there aren't many real undecided voters left. If you push those who say they are undecided to say who they might consider, many are not considering either major candidate. Therefore, the pool of undecideds that are actually gettable by either Clinton or Trump is tiny.'"
A senior Clinton adviser confirmed to the Washington Examiner that for Kaine, a key debate objective was to remind the national audience once again of Trump's stream of insults directed towards women, Mexicans, and President Barack Obama.
Right now, as Politico reported recently, the Clinton campaign is mostly focused on what the composition of the electorate will look like on election day, which essentially entails re-energising the Obama coalition (Latinos, African Americans, young voters, unmarried women), converting registered or unregistered voters into likely or certain voters, and winning over those drifting to minor parties.
These voters were the real target of Kaine's frequent airing out of Trump's bigoted quotes, along with college educated whites, especially women, who (Dems hope) will remain alienated by Trump's temperament, which Kaine also highlighted.
The story that the latest polling has been telling is that those voters are on track to giving Clinton a winning coalition.
As Nate Cohn of the New York Times explains, Clinton's lead right now is partly due to a surge in enthusiasm among core Dem voters, as well as her strength among well educated white voters, which is enabling her to move ahead in more diverse states like Florida, Virginia, Colorado, and North Carolina.
Trump continues to remain a real threat in Rust Belt states, because he's maintaining very durable support among working class whites.
But as Cohn notes, if the current state of affairs holds, there just won't be "much room for him to fight back with additional gains among white working-class voters".
Even Pence's undeniably solid performance confirmed the basic outlines of this state of affairs. Pence was much more in command of policy, had a smoother, more likable delivery, and prosecuted a stronger case against Clinton than Trump did at his debate.
But even there, the intended audience for Pence's arguments - the attacks on Clinton's emails and the Clinton Foundation; the tale that as Secretary of State, Clinton left the Middle East in flames - was mostly GOP base voters.
While such attacks might keep alive doubts about Clinton in the minds of college educated whites and suburban women, what did Pence say that might get them to reconsider their potentially irreversible alienation at the hands of Trump's ignorance, bigotry, chauvinism and unstable temperament?
He barely even tried. In essence, what Pence could not successfully do is persuade college educated whites and suburban women that Trump is not a racist, is not sexist, and is not dangerously insane.
All of which is to say that both sides pumped their respective bases, but only one side continued making the very same case to educated whites, particularly women, that has already proven persuasive (as the polls indicate) to them.
It is possible that Trump's strength among working class whites can still enable him to win, provided something happens that enables him to pull off wins in multiple diverse states. But it's hard to see how Pence did anything to alter the losing hand Trump now seems to hold.
A CNN instant poll of debate watchers found that they thought by 48-42 that Pence did the better job, and Pence was seen as the more likable candidate by 53-37.
But the poll also found that watchers thought by 48-41 that Kaine had a better understanding of the issues, and crucially, they said by 58-35 that Kaine did the better job of defending his running-mate.