Gordon Brown famously brought his moral compass to the prime ministership. Boris Johnson, notoriously, did not. Under Keir Starmer, there is a moral compass in Downing Street once more. But something else has gone missing. Too often, Labour now seems to lack not a moral compass, but a fully functioning political one. It has never needed one more than it does today. Recent history suggests that any government’s political compass is a powerful embodiment of its survival instinct. The compass addresses the dangers, as well as the attractions, of a course of action. It recognises that the way an action will be portrayed is a reality as powerful as the intention behind it. It prioritises grip, speed and proactive flair, as well as discipline about priorities. The most recent evidence that Labour’s political compass has been lost is in the unnecessary and overwrought row about its role in the US election. Here, once again, Labour has allowed its actions to be defined by its critics. As such, it fits a pattern: the failure to spot the danger in the freebies-for-ministers revelations; the tangled rise and fall of Sue Gray; the peremptory cull of winter fuel payments. With a good political compass, all of these could have been avoided. The US election row shows how easily a small fumble can become a needlessly damaging challenge. Kamala Harris and Donald Trump are already running massively well-funded campaign leviathans. They don’t need Labour’s assistance. But a formal Labour intervention would also be foolish, potentially embarrassing for Harris, and a propaganda gift for Trump. No one in the Labour chain of command seems to have spotted the dangers. Where was Labour’s political acumen when it was needed? It is not clear whether Labour Harris campaigners were given advance legal advice about the rules on foreign involvement in US elections. Labour says the volunteers have not been paid or supported in other ways. The Trump campaign alleges they may have. The now withdrawn comment on LinkedIn by Labour’s head of operations Sofia Patel that “we will sort your housing” could imply some party subsidy. That Patel is a full-time Labour official could arguably be read as direct Labour involvement too. But here’s the point. Where were Labour’s political antennae in all this? For the last few weeks, perhaps like some of you, I have been bombarded with US emails asking me to donate to the Harris campaign. And, yes, part of me wants to do so. But, as a foreign national, I would be committing a federal offence by donating, and the Harris campaign would be doing the same by accepting one. So I cheer from the sidelines and stay within the rules. It would be surprising if nobody at the Labour party stopped to ask themselves similar questions. But they should have done. That’s because Labour’s responsibility goes beyond not breaking any laws. It extends to the prime minister’s, the party’s and the country’s relations with Trump if he is elected next month. Here, in particular, is where an embarrassment should have been scrupulously avoided. Many readers will be bridling at all this. They will say Nigel Farage’s US campaigning is far bigger but gets far less scrutiny. Or that the rightwing press is out to discredit anything that Labour does. Or that nothing Labour may do is remotely as dangerous as the Russian or Chinese tampering with western elections. They might go further, by saying that all UK parties get involved in US politics a bit, as ex-Tory minister Robert Buckland has acknowledged, so it is wrong to single out Labour. Or that it’s useful for political professionals to get a close-up view of the latest campaign techniques in other countries. Perhaps, above all, they will say that the defeat of Donald Trump is so important that it has to be our business too. Some will also point out that this row is a textbook dead-cat manoeuvre. Throw a dead cat on the table and everyone starts obsessing about the new distraction, not something really important. On Wednesday, the environment secretary Steve Reed went on Radio 4’s Today programme intending to talk about the shambolic state of the water industry, but had to talk about Labour and Trump first. Substance was ousted by marginalia. There is some truth in all of these objections. But they all miss the main one. The point is that Labour is in government. The UK and the US are allies. Allies don’t mess in one another’s elections. If they did, the voters would be angry, legitimately so. Imagine the indignation here if a rich megalomaniac offered UK voters the kind of rewards Elon Musk is currently deploying in Pennsylvania and other swing states. It could happen, and the UK government should look at the relevant law to make sure it does not. Getting involved in any foreign election puts the national interest on the line. Sensible governments with a strong sense of self-preservation don’t mess with that. Labour has rightly tried to build a relationship with Trump, as any UK government always would. It may not work – and probably will not – but the national interest requires them to try. Stumbling into a row about a few Labour volunteers is just bad politics, even though most UK citizens want Trump to lose. Labour should not have done it. It is hard to dispute in principle that Labour activists, even employees, with an interest in US politics should be able to volunteer and learn on the campaign trail. Rightly or wrongly, many Labour people are always keen to plug themselves into a Democratic party campaign. Similarly, quite a few Tories are plugged into the Republicans. You can, even so, criticise this for being too starry-eyed and naive. There’s a touch of West Wing envy in the fan trek that UK politicos make across the Atlantic every four years. Yet the longer I myself worked in the US, which I did for four years, the clearer I became that the more you know about US politics, the more foreign it feels. European countries offer just as many practical lessons. But German politics or Irish politics are not glamorous. In the end, the US election involvement row, along with the other rows that preceded it, are telling Labour something that still requires corrective action. Given how obvious it was for so long that Labour would win in 2024, it has proved remarkably badly prepared for government. This needs tackling before the next avoidable stumble occurs. Starmer is now at risk of allowing himself to be defined in the long term by stumbles over short-term issues that he considers marginal. This may well be an unfair outcome, but it is a real possibility. He cannot afford much more of it. A political compass would be telling him this. Everything now depends on trusting the compass unerringly over the budget next week. It will be a defining test. Martin Kettle is a Guardian columnist