Hint: It probably wasn’t the candidate who took a long look at his watch as his energy and focus began to run low. For the first hour, Joe Biden’s performance suggested that four days of rest had prepared him for battle, with snappy answers and rebuttals. After that, however, Biden started recycling his canned lines, and Donald Trump pounced on them by underscoring his argument about Biden being a “typical politician.”

Late in the debate, Biden appeared to be losing interest as well as losing steam:

John Fund noticed the moment and its historical significance immediately. Fund also wondered why Biden wore it in the first place:

Mediaite and other outlets also noticed it:

The moment came as moderator Kristen Welker asked the candidates about climate change, noting the candidates “have very different visions on climate change.” Cameras caught Biden extending his arm, pulling out his watch and gazing at it as Welker spoke.

Observers compared the incident to the 1992 debate between former President George H.W. Bush, then-Arkansas Gov. Bill Clinton and Ross Perot. Bush received widespread criticism that year for checking his watch during the debate, with naysayers saying he looked “impatient.”

This was just one of a series of errors made by Biden in the final third of last night’s debate. The format changes ended up improving the performances of both candidates, allowing for better answers to moderator Kristin Welker’s questions, and the microphone control never felt intrusive. And for about the first hour, it seemed both men were evenly matched.

After that, though, Biden clearly started running out of gas. His answers began meandering, and he seemed less able to organize his thoughts outside of slogans. In a couple of cases, prepared slogans that had worked in the moment for Biden earlier in the debate got dropped in as almost non-sequiturs, attempts to change the subject when Biden seemed lost on a question or rebuttal. At the same time, Trump ramped up his attacks on Biden’s answers and began to effectively hammer Biden on having been in Washington for 47 years and yet having done little to achieve what Biden says he’ll do in the next four.

At one point, Trump pounded him on a point about criminal-justice reform, asking him why he hadn’t accomplished it in eight years of the Obama presidency. “We had a Republican Congress,” Biden replied in a weak voice, “that’s the answer.” Biden and Obama had a filibuster-proof Democratic Congress their first two years, however, and they never even pushed criminal-justice reform. Not to mention that Trump got his criminal-justice program through a Republican Congress.

This was just moments before the watch check, by the way, and it was clear that Biden had had enough at this point. Even on four days’ rest, Biden got gassed — which is what led to his pledge to end the oil industry at the very end of the climate-change question Welker was articulating as Biden checked his watch.

Up to that point, I would have rated this a tie, as Frank Luntz did overall:

That seems to be the sixty-minute view rather than the ninety-minute view. In the first place, the descriptions from Luntz’ own focus group tend to favor Trump, at least in Luntz’ telling. Trump made an impression with his change of approach, while Biden was “vague, unspecific, elusive” when allowed to speak. But more importantly, Biden took a lot of punches in the last third of the debate, the part that people will remember most.

Piers Morgan, not exactly a die-hard Trump fan, has a clearer eye on what took place last night:

Instead of the ranting, deluded, narcissistic buffoon we got last time, this was a far calmer, measured, focused, well-prepared, non-scary and even empathetic performance by the president. …

It’s not Biden’s fault, given he’s nearly 80, but he has half the energy, dynamism and vision of Barack Obama and that’s a problem when compared to Trump who, love him or hate him, always bursts with charismatic vitality.

The president may be a polarizing, inflammatory man with barely any experience of public service.

But he skilfully exploited that apparent weakness as a strength – repeatedly berating Biden for not doing the things he’s now promising to do on issues like healthcare and immigration during his eight years as vice president.

‘You keep talking about all these things you’re going to do,’ Trump sneered. ‘Why didn’t you get it done? All talk and no action, just like a politician.’

It’s a good point, so much so that at one stage rattled Biden even chucked Obama under the bus over why he hadn’t done more to tackle immigration, exclaiming: ‘It took too long to get it right, I’ll be president of the United States, not vice president.’

“Rattled” is a good description of Biden down the stretch last night. But the mistakes began earlier than that, too, especially Biden’s attempt to defuse the Hunter Biden story with a pre-emptive attack on Rudy Giuliani. Neither Trump nor Welker had brought up Hunter at that point, but Biden opened the door to more than an hour of references at the 21-minute mark:

His own national security advisor told him that what is happening with his buddy — well, I won’t, I shouldn’t — I will — his buddy Rudy Giuliani. He’s being used as a Russian pawn. He’s being fed information that is Russian, that is not true.

Having opened that door, Trump gladly went through it — repeatedly. Just before the debate, Hunter Biden’s former business partner Tony Bobulinski had held a press conference to corroborate the New York Post’s reporting about Hunter’s e-mails and announced his plans to cooperate with the FBI and the Senate Homeland Security Committee about the deal with the China firm at the center of the controversy. It was an exceedingly strange time to claim it was Russian information, and Trump scored on Biden’s “Russia Russia Russia” responses.

This was a clear win by Trump, and he needed it. Will it move the needle? Maybe. Nearly forty million ballots had already been cast by the start of the debate, which is why Trump really needed a performance like this the last time. Still, for the eighty-million plus Americans who have not yet cast ballots, it’s a good look at Biden without his media cover, and the truth is that Biden simply doesn’t have the stamina for this job. Even on four days’ rest, Biden gets gassed out after sixty minutes and can’t keep up.

As for Welker’s moderation, it was a big improvement over Chris Wallace, with the help of the format change. She still used an agenda seemingly calculated for Biden’s advantage, but the most potent criticism of it was that it was essentially a rerun of Wallace’s topic list in the first debate. We learned very little about foreign policy, which used to be Biden’s supposed strong point, the war in Afghanistan never got discussed at all, and neither did the Middle East and American leadership. In fact, other than China, Welker never discussed foreign policy at all, which is very strange since that’s one of the few nearly exclusive domains of the presidency. Welker did a good job managing the back and forth, but other than that she was strikingly unoriginal.