JD Vance tries his best not to appear funny – and that makes him seem even more menacing | Emma Brockes

TAs I watched JD Vance's exchange with Tim Walz in Tuesday night's vice-presidential debate, the overriding and at times darkly funny impression was that Vance was all about demonstrating to America how over-the-top non-funny he is. There's nothing to see here! Just a guy with a calm expression, nice manners, a noble desire to find “common sense, bipartisan solutions,” and a cute little quiff. His demeanor was so relaxed, so urbane, that at points during the debate he could have twirled a stick and slinked around the corner like Top Cat.

While the event itself is unlikely to influence the election, the performance of the two vice presidential contenders was a useful indicator of where each campaign sees its weaknesses. Both men were required to be honest, a difficult task in such a rehearsed and high-pressure environment, but only Vance was tasked with displaying normalcy – which he succeeded to some extent. Walz, meanwhile, struggled to back up his charm with anything more steely and purposeful than familiarity. While a presidential candidate can be all flamboyants and jazz peddlers, the vice president's job is to be a sober voice in the room — and for 90 minutes, both men tried to outdo each other.

The result was, in some ways, a pleasantly non-dramatic exchange, with each man being extremely polite to the other. When Walz mentioned that his son had witnessed a shooting at a community center, Vance struck exactly the tone he usually struggled with – he was recognizably human – and immediately expressed his sympathy. Walz, meanwhile, appeared conciliatory on the question of how another school shooting could be prevented, acknowledging that his opponent was fundamentally opposed to the murder of young children, at least in principle. For Walz, however, the debate was more difficult from the start, given how low expectations were for his rival.

And at first, Walz seemed to mess things up. He was, he said, not a natural debater, happier charming voters while buying a donut or holding a cat than facing someone on stage. In contrast, Vance is absolutely the champion debater you knew from college, right down to his little shark eyes and resting, smug face. (Walz's resting face ranged from “give me a break” incredulity to full-blown “oh-god-we're-all-going-to-die-scared-eyes,” and by the end of the debate the corners of his mouth were drooping so hard, that he looked like Marlon Brando in The Godfather.)

Given the bias we bring to the party at this stage, for the sake of argument, I have tried to consider the possibility that Vance's reasonable stance means a reasonable attitude, and to view Walz's underwhelming performance through the eyes of those who are with Trump sympathize. Maybe Walz's folksy charm is just a cover for something more mercenary? Maybe Vance isn't as bad as he seemed? But then he talked about how restricting abortion was a way to “give women more options” and I thought, “You creepy little idiot,” and was back to square one.

That's the crux of the matter with politicians like Vance, whose job it is to put a civilized face on Trumpist extremism. In a calm, measured voice, he defended the creation of conditions in which miscarrying women die while traveling across state borders because they are denied adequate health care locally. Encouragingly, he suggested that school shootings in the US could be addressed by making school “doors” and “windows” “stronger.” He argued that the real victims of the U.S. immigration crisis are border patrol agents “who just want the power to do their jobs.”

And when Walz asked him point-blank if he thought Trump lost the 2020 election, he dodged the question entirely. “I'm pretty shocked,” Walz said, and he looked it. There's arguably something weirder about presenting fanatical, life-threatening positions in the urbane tone of someone who has a lot to offer us all, and yet at times during the debate Vance's more superficial strangeness was still visible. I laughed out loud when he described Usha, his wife, as a “gorgeous woman who is an incredible mother to our three wonderful children and also a very, very brilliant corporate litigator.” The end result? Vance is really scary.

Of course he is also dangerous. There was a single, fleeting moment when I thought Vance had dropped his mask, and that was 30 minutes later when Walz mentioned Springfield, Ohio, in reference to Vance's lie about Haitian immigrants eating pets. Walz, playing the more merciful-than-thou game, admitted that Senator Vance was genuinely interested in solving the immigration problem, but that he was only making it worse “by standing with Donald Trump.” It was as close to accusing the man of crass, self-serving, almost psychopathic venality as the tone of the exchange allowed. A flash of anger crossed Vance's face before the banality of his demeanor returned.