Keir Starmer has found his winning position – as the antidote to Liz Truss

It takes a truly abysmal prime minister to make the opposition leader’s job look easy. It is the toughest gig in Westminster. You struggle to get noticed until you make a mistake, when the pillory is merciless. If you attack the government without a better offer, you are carping from the sidelines. When you come up with a better plan, the government nicks it. If you have ambitions but few policies, critics say there is no substance. If you go into detail, pundits lament an absence of vision.

Any strategy to beat an incumbent party involves appealing to its voters, which is denounced as treason by your own activists. You must generate excitement about the prospect of change, while emitting reassurance that the change is not alarming.

Keir Starmer has had mixed success grappling with those dilemmas and it isn’t hard to imagine scenarios where Labour’s conference in Liverpool was mired in recrimination over missed opportunities and consumed by factional feuding. Liz Truss might have been enjoying a bounce in opinion polls. The Tories’ offer to subsidise the nation’s energy bills through the winter might have closed down a fruitful line of opposition attack. There was public goodwill available to a new prime minister who benefited from the paramount quality of not being Boris Johnson.

But Truss has squandered that potential with more efficiency than Labour dared hope was possible. If Starmer could have asked Downing Street for a single favour, he might have requested that the chancellor do exactly what he did last Friday. Kwasi Kwarteng’s mini-budget was exquisitely designed to destroy what is left of Conservative claims to be serious stewards of the economy, while advertising the party as a factory of favours for the super-rich.

The errors are unforced but that doesn’t mean the benefits that accrue to Labour are pure luck. Starmer is well placed to capitalise on Kwarteng’s mistakes because he and Rachel Reeves, the shadow chancellor, have manoeuvred their party into a position of fiscal sobriety. It is not enough for the Tories to shrug off the mantle of sound money. Labour has to pick it up and try it on without soliciting sniggers of derision.

Related: How did Keir Starmer’s speech to the Labour conference go? Our panel’s verdict

Starmer has achieved that with only meagre, grudging credit from the right of his party, which complained that he was too squeamish in repudiation of Jeremy Corbyn’s legacy, and even less from the left, where that legacy is not up for repudiation. All sides are given to fretting about wooden performances and a lack of contagious phrases. The leader’s keynote speech in Liverpool on Tuesday marked out the terrain on which Labour must fight the next election with more precision than panache, but the delivery was assured. It expressed new confidence with credible foundations.

Starmer explicitly and correctly identified the electoral landing zone as the centre ground of British politics. It is a phrase that can trigger allergic reactions in activists who associate it with mid-90s campaign tactics. In the left account, centrism mortgaged the party’s soul for Tory votes and is not relevant to the task of winning in the 21st century.

But Starmer’s map follows the contours of a changed political landscape. The pledge of a “Great British Energy” company is recognition that, on matters of public ownership at least, the centre is not where it was when New Labour sprawled across it in 1997. The broader argument – voters want a government that is prudent with their money, while also investing in public services – is not new, but still true.

Starmer did not give his audience a complete blueprint for government or a display of rhetorical pyrotechnics, but he didn’t need them. He needed to look like a man who could be trusted to run a country better than Truss. A portion of any party’s frustration with its leader expresses the gap between politics as a minority interest for enthusiasts and politics as most people see it, most of the time. It is the difference between fandom and passing interest. Fans value things like consistency and rhetorical uplift. They make new words by inserting “ism” after a leader’s name; they ask whether the new word is a creed that can be illuminated as a vision.

Politics fans will always find Starmer frustrating because he isn’t very ism-able. That is sometimes mistaken for being unprincipled or shallow. To the doctrinaire mind, the absence of doctrine indicates a shortage of belief. But most people go about their lives carrying values and principles in their heads without feeling the need to codify them as a system and test it for internal consistency. They judge politicians on the basis of impressions formed about their character, using the normal human metrics – does someone seem decent, trustworthy, kind, capable, sane?

Those judgments can be wrong, but views of a politician are rarely changed by adoption of a theoretical label or by their enemies’ attempts to pin one on them. Ideological purity isn’t in most people’s repertoire of things to care about one way or another. Voters in Labour’s former industrial heartlands didn’t reject Corbyn in 2019 because they thought nationalising railways was a slippery slope to the gulag, but because he came across as an unpatriotic crank who shouldn’t be in charge of the nation’s money or its army.

Those things cannot be said of Starmer, which is a large part of the reason why his party has a double-digit poll lead. If that advantage can be sustained, Tory MPs will panic. Expectation of a rout at the next election could acquire the self-sustaining momentum that makes oppositions look like governments-in-waiting. If that happens, no one will care if there is such a thing as Starmerism.

It will help that the prime minister is a maniac. It is the trait that comes across in the testimony of advisers and civil servants who have worked with her. They describe fundamentalist attachment to the free-market ideas that were manifest as policy in last week’s disastrous mini-budget, and a habit of dismissing rational caution as spoilsport cowardice. It is said that Truss’s fanatical streak often needed reining in by No 10 when she was a minister. Now it is unbridled. Character flaws of that magnitude cannot be hidden from the public.

There will doubtless be times to come when Keir Starmer fails to press home all of his advantages. He is sure to plod prosaically through moments when the Labour faithful crave campaigning poetry. They would be a lot angrier if he wasn’t winning, and he is. Last week, Truss made opposition look easy for him. But it is never easy. His job this week was to make her job harder in turn. And he has.

• Rafael Behr is a Guardian columnist