Will JD Vance’s debate performance help swing the pendulum back to Trump?

There is a widespread view that vice-presidential candidates do not have a great bearing on the result of a US election – and that it is overwhelmingly the presidential nominee that determines people’s vote.

That argument extends to the set-piece vice-presidential debate. Where the televised presidential head-to-heads are seen as potential game changers, the vice-presidents’ duel is seen more as a duty, rather than something that will actually make a difference.

That might not apply this year, for three reasons. The first is that this vice-presidential debate threw up a clear winner and may have had the capacity to change viewers’ perceptions. The second is that there are peculiarities about this year’s election that place the running mates in the frame more than usual, and the third reason is the closeness of the race.

The clear winner on Tuesday night was Donald Trump’s running mate, JD Vance. From the first question – on the escalating conflict in the Middle East – Vance came across as more fluent, more articulate and better informed than Kamala Harris’s running mate, Tim Walz.

Walz may have been unlucky that the first question was – unusually – on foreign policy and he seemed thrown by this, but this was not a good impression for someone putting himself forward to be the proverbial “heartbeat away”. Here and elsewhere, he seemed hesitant and searching for words. He flailed especially when pressed about whether – as he had previously said – he had really been in China during the Tiananmen Square massacre. He eventually conceded that he might have “misspoken”.

He also often fell back on prepared lines and references to Kamala Harris. This might have added a nice touch of loyalty, but left doubts about his autonomy. He was on firmer ground when citing the policies he had introduced as governor of Minnesota – and gained confidence as the debate wore on, but his early performance raised questions about how comfortable he might be in national, as opposed to state-level, politics.

It will probably be a relief to the Harris team that this was the only vice-presidential debate – and that early voting has already started, so not all voters will be influenced one way or the other. He is clearly far stronger as a stump performer – where his experience as a high school football coach comes into its own and he can make a direct human appeal to a live audience – than in an empty television studio. He will be able to make up ground in the month of campaigning that remains, but some damage may have been done.

That damage may be compounded by the fact that his opponent, JD Vance, created a more positive impression than his many foes surely expected. He came across as a good speaker, urbane and nimble in debate. He was also polished and considered at times in a way that could banish some of the negative perceptions that have stuck to him so far – as a hick from the backwoods, a rigid conservative, and little more than a mouthpiece for Trump.

He managed, for instance, to present his position on abortion – a subject seen as a plus for Harris, especially among women voters – as more modulated than it has hitherto appeared. He denied he wanted a ban on abortion, presenting his stance rather in the context of states’ rights (which the Roe v Wade ruling was), rather than an ethical position derived from his Catholic faith. Could this influence some undecided voters? Perhaps.

Many will surely find it difficult to look past his conduct on the campaign trail thus far, such as his lie that Haitian immigrants in Springfield, Ohio are eating residents’ pets. They also may see his better-than-expected performance as laundering his boss’s reputation – his representation of some of Trump’s positions and prior remarks was generous at best. Nevertheless, it was not the Trump v Kamala-level disaster for the Republican candidate that some foresaw.

The second reason why this debate may matter is that the running mates, on both sides, are more in the frame than often and they have quite a lot in common. Both are from modest backgrounds in the US heartland – Walz, who grew up on a farm in Nebraska and moved to Minnesota, and Vance, originally from Kentucky, grew up mostly in Ohio. Money was short in both households; both served in the military – Walz in the national guard, Vance in the marines – and both used the GI Bill as their gateway to higher education. This gives both an appealing backstory for many Americans.

They are both opposites in many ways to their respective running mates – Harris from a professional background in California, and Trump the quintessential mogul, showman and hustler – and they were selected in part to “balance” the ticket and compensate for perceived shortcomings of the main nominees. But their selection also reflects on the presidential candidate, as an early gauge of their ability to pick people.

Conventional wisdom was that while Walz was an asset to Harris, Vance risked being a liability to Trump – not least because he was chosen as a foil to Joe Biden before Harris became the Democratic nominee. His performance in the TV debate, however, helped give the lie to that, as he proved more flexible, quieter and less crassly outspoken than at times on the stump.

Harris chose Walz, on the other hand, in the full knowledge that she was facing Trump and Vance, and she needed someone with a non-metropolitan background and a popular touch. The downside, it is now clear, is his readiness – or lack thereof – for the big time.

It might also be observed that the atmosphere of this debate was genial and respectful in a way that the Trump-Harris debate most definitely was not. It concluded in a lengthy handshake, and what appeared to be warm words between the couples. But again, it could be Vance who chiefly benefits from this, given his image in some quarters as a simplistic attack-dog.

During the debate itself, it was Vance who showed a modicum of charm, while Walz seemed to make a conscious effort to temper his naturally affable demeanour. There may be benefits in looking tough in a US TV debate, but there is a difference between tough and unapproachable. Walz’s humane side featured a good deal less during the 90-minute debate than it generally does in just 10 minutes on the stump.

And the contrasting impressions could matter. Because – the third reason for the significance of this debate – of the closeness of this year’s race. From a late start, as a largely unknown vice-president, Kamala Harris has worked miracles in catching up and even overtaking Donald Trump in the polls. But it has not all been plain sailing; her command of policy, especially economic policy, does not always generate confidence, and she might have benefited from the tempering that most successful candidates receive from the long primary process she missed.

Donald Trump, on the other hand, seems back in his stride, after being thrown by the withdrawal of Biden and by two assassination attempts. He is back at mass rallies taking questions from fans in his inimitable way. And it cannot be repeated too often than national polls can be deceptive. It is in the half-dozen “swing” or “battleground” states where, as always, the race will be won or lost. You can criticise the electoral college system, but it is delegates, not the popular vote, that decide a US presidential election, and here there is still all to play for.

If Trump eventually prevails, he will doubtless claim all the credit. But, by adjusting his tone for a mass TV audience, may JD Vance have helped to “detoxify” some of his running mate’s policy excesses, convincing just enough “undecided" voters that he is not the bogeyman they once supposed? And will it be enough to tip the scales? In a few short weeks, we may get our answer.