It is a shocker that about 100 current and former Labour party staffers are hopping over the pond to campaign for Kamala Harris in swing states as the race for the White House enters the final, feverish furlong. A measly 100? Is that the best they could do? Labour will often manage to get more of its people knocking on doors and handing out leaflets for a humdrum British byelection in which nothing more is in play than who gets to be MP for Slumberborough. Much more is at stake in a US presidential contest that, with fewer than 10 days to go, the polls have as a coin-toss. Only Americans get to vote, but the world will have to cope with the consequences if Donald Trump again darkens the door of the White House. The fate of Ukraine, the future of Nato, the stability of the global economy, the response to the climate crisis, the cohesion of the democracies in the struggle with an axis of autocracies, and plausibly even the freedoms of America itself, all this is on the ballot in 2024. Given the vertiginous scale of the stakes, you might argue that it is remarkable how few Labour people are volunteering to help out their fellow progressives across the Atlantic. The ostensible “controversy” about Labour being guilty of “foreign interference” in the American election is a campaign stunt, a synthetic confection whipped up by Team Trump, which has been given extra froth here by Nigel Farage and other Maga cheerleaders on our shores. It is as phoney as a three-dollar bill. There is a long and legitimate tradition of ideas-swapping and mutual assistance between British and American politicians and operatives. Labour and the US Democrats are sister parties. The Tories have historically had an affinity with the Republicans. While the more moderate British right contains many never-Trumpers, its more extreme iterations are among his greatest fans. Mr Farage, himself no stranger to campaigning in the US, didn’t see anything wrong with attending the Republican convention in Milwaukee in July. There was nothing odd, still less sinister, about Morgan McSweeney, Labour’s campaign chief at the time, and Matthew Doyle, its director of communications, being present at the Democrats’ convention in Chicago in the summer. It would have been more weirdly noteworthy had no Labour people been in the Windy City to witness the crowning of Ms Harris as her party’s nominee. The Trump campaign has nevertheless seized on a couple of Labour officials being in Chicago and 100 volunteers going on the knocker as the basis for its ludicrous charge that this amounts to “anti-American” meddling in the election. The complaining letter from the Trump legal team to the Federal Election Commission cites the American war for independence while misspelling Great Britain as “Great Britian”. The attack is designed to dirty up Ms Harris by suggesting her campaign is so “flailing” that it is having to seek help from abroad – and, gosh, from the former colonial power. Well, if the topic is the subversion of American democracy, the violent attempt to prevent certification of the last presidential election result when a Trumpite mob was incited to storm the Capitol was a rather graver threat than some Labour volunteers tramping around Pennsylvania trying to find undecided voters. On the recent testimony of John Kelly, a retired marine general who was chief of staff in the Trump White House for 18 months, the once and wannabe future president fits “the general definition of fascist” and told him that Hitler “did some good things”. The most damning observations about the character and conduct of Mr Trump have invariably come not from his opponents but from those who have worked with him most closely. Another clue not to take Trump propagandists seriously when they pose as guardians of US democracy is when they brand Sir Keir Starmer’s Labour as “far left”. That suggests a lack of familiarity with British politics. Or perhaps they assume that the intended audience among American voters are entirely clueless about the ideological complexion of the UK’s government. Here I think we get to the real lesson of this story. It is not that Labour people want to see a Trump defeat and a Harris victory – both obvious and natural – however much Sir Keir feels he has to hedge his bets by wearing a mask of neutrality. No, the main moral for Britain’s government is that Mr Trump does not give a toss what it thinks. If a synthetic transatlantic spat might tilt the odds of him regaining the presidency even by a tiny bit, he will happily sanction an assault on the governing party of what is supposed to be one of America’s most important allies. This contempt for Britain is not wholly a revelation. Conservative prime ministers who tried to worm their way into his affections got scant reward for their demeaning efforts. He congratulated Boris Johnson for being “Britain Trump” (sic), but denied him the US trade deal he was so desperate for. Theresa May was treated with undisguised disdain and her attempts to butter him up included massaging his ego with tea at Windsor Castle one year and a full-blown state visit the next. The late Queen was not amused by her “very rude” guest. Mrs May later wrote that “she never knew what to expect” from him and heard him “question core tenets of the transatlantic alliance”. So Sir Keir should avoid being seduced by any fantasy that he will be able to be a “Trump whisperer” who can “handle” the American. Contingency planning by the British government ought to work on the assumption that they are going to find it a howling nightmare if he gets back into the White House. This is a sensitive spot for the prime minister. Speaking to reporters accompanying him to the Commonwealth summit in Samoa, Sir Keir repeated the standard line that he will work with whoever America puts in the White House and can sustain a “good relationship” with Trump. While we can understand why he feels compelled to say that, there is something a bit wince-inducing about Downing Street’s efforts to persuade everyone that they will have a fine bromance. Were you aware that the two men had a two-hour dinner at Trump Tower in New York last month? Some of the Labour leader’s people bang on about that dinner as if it were the most historically significant meeting over food since the Last Supper. The truth universally acknowledged by officials in private, while strenuously avoided by the prime minister in public, is that a second Trump presidency will be a clear and present danger to the UK’s most vital national interests. The fight to preserve the freedom and territorial integrity of Ukraine is rightly regarded by Number 10 as critical to protecting Europe from further Russian aggression. Sir Keir’s recent pledge to support the Ukrainians “for as long as it takes” is cast into deep doubt by Mr Trump’s tirades against Volodymyr Zelenskyy, loathing of giving further assistance to the Ukrainians and frequent suggestions that he will sell them out to Vladimir Putin. The American commitment to Nato, the backbone of UK defence strategy since the 1940s, will be thrown into grave doubt. Britain has just signed a new defence collaboration treaty with Germany. The proximity of this event to the US election is not a coincidence. Trumpian hostility towards free trade is another danger to the UK. He has vowed to impose not just swingeingly high tariffs on all imports from China but also a hefty increase on those into the US from the EU. Brexit Britain could find itself the piggy in the middle of a highly punishing trade war. That’s not going to be conducive to fulfilling Sir Keir’s ambitions to boost the performance of our economy. A Trump victory will have a bigger impact on our prosperity than Rachel Reeves giving a tweak to her fiscal rules. Accelerating the green transition is a signature theme of the Labour government. As he did last time he was in the White House, Mr Trump would rip up American commitments to addressing the climate crisis. Whichever direction you look, what sources in Whitehall euphemistically refer to as “the Trump problem” will generate a scary array of threats to the UK’s interests and values that will make Sir Keir’s prime ministership a whole lot more difficult. So the surprise is not that some Labour volunteers are trying to lend a hand to Kamala Harris. The surprise is that more haven’t joined the effort to stop Donald Trump before it is too late. Andrew Rawnsley is the Chief Political Commentator of the Observer