It is usually just a week, but sometimes longer. The hours are long, the socialising limited, and there is no reward beyond free accommodation in a shared house, recalls one Labour staffer who spent three weeks knocking on doors and ferrying leaflets for the 2008 campaign to put Barack Obama, then a junior senator from Illinois, in the White House. What volunteering in a US election does offer is a walk-on part in a moment in history. “I arrived on the Saturday, and I was put to work on the Sunday and I worked seven days a week for three weeks, often ending at 10pm,” the staffer recalled. “There might be a beer after work but that was about it. There was some suspicion in what were predominantly black neighbourhoods of a white man with a clipboard knocking on doors – and then they heard the English accent. “The response was generally: ‘What do you want?’ But as soon as you said you were from the Obama campaign, the doors opened: ‘Come on in.’ And that was special.” A post last week on LinkedIn by Sofia Patel, Labour’s head of operations, has started a peculiar row over a longstanding practice of British and American politicos: lending their support to sister parties across the Atlantic. “I have nearly 100 Labour party staff (current and former) going to the US in the next few weeks heading to North Carolina, Nevada, Pennsylvania and Virginia,” Patel wrote. “I have 10 spots available for anyone available to head to the battleground state of North Carolina – we will sort your housing. Email me on labourforkamala@gmail.com if you’re interested.” The message may seem innocuous enough, but with the US presidential race too close to call and with less than three weeks to go, no potential wedge issue is being wasted, and the suggestion of foreign interference has some power to change minds in American politics. Under Federal Election Commission rules, foreign volunteers on US campaigns are permissible as long as they are not compensated for their work, and in Patel’s message the Trump campaign detected evidence of such remuneration in the form of sponsored accommodation. The campaign filed a complaint with the Federal Election Commission in Washington seeking an immediate investigation into alleged “blatant foreign interference”. “When representatives of the British government previously sought to go door-to-door in America, it did not end well for them,” the Trump presidential campaign’s deputy general counsel declared, in an apparent reference to the war of independence. Thrown into the complaint for good measure was that a number of senior Labour party staff – namely, Morgan McSweeney, the prime minister’s chief of staff, and Matthew Doyle, Downing Street director of communications – also attended the Democratic convention in Chicago and met Kamala Harris’s campaign team. The British prime minister, Keir Starmer, was moved to deny meddling in the US presidential election as he flew to the Commonwealth heads of government summit in Samoa in the South Pacific. “The Labour party has volunteers; [they] have gone over pretty much every election,” he said. “They’re doing it in their spare time. They’re doing it as volunteers. They’re staying I think with other volunteers over there.” Lord Wood of Anfield, a former No 10 adviser to Gordon Brown, said such arrangements were not unusual and that he had facilitated volunteering himself. He said: “Labour people, staffers and others, have been going over to volunteer for the Dems – which is our sister party after all – as long as I have been involved with Labour. Always using their own money, though often asking people like me for contacts.” It is understood that officials in organisations such as Labour Students and Democrats Abroad, a group that has assisted US citizens in the UK to take part in elections at home, have also in the past organised for British volunteers to help out in swing states. The moment of maximum cooperation was perhaps during the era of Bill Clinton and Tony Blair, when the “third way” in western politics was in the ascendancy and mutually supportive thinktanks made the connections. But such cooperation is certainly not unknown on the right of politics. “There were lots of Tories over helping the John McCain presidential campaign,” recalled the Labour staffer of the 2008 election. In 2015, a team organised by the US Young Republicans International Committee, a movement for those aged 18-40, helped out in the marginal seat of Enfield North, and the constituency of Aylesbury, where the Conservatives were being challenged by the UK Independence party. Then there are those who cross party lines. Simon Burns, a Conservative MP between 1987 and 2017, worked on his gap year in 1972 for George McGovern’s presidential campaign against Richard Nixon. He went on to help secure the elections to the Senate and Congress of Ted and Joe Kennedy, respectively, and he campaigned for Hillary Clinton in 2016. John Healey, the British defence secretary, suggested the Trump campaign had created a synthetic row. “This is in the middle of an election campaign, that’s the way that politics works,” he said. But this is not the first time this issue has blown up. In 2018, the Bernie Sanders campaign agreed to pay a $14,500 fine (£11,190) to the FEC after the agency ruled that his 2016 presidential campaign had accepted an illegal contribution from the Australian Labor party. The FEC found against Sanders on the basis that the Australian volunteers had received a stipend from the Labor party and had their flights paid for. There is no suggestion that anything like that happened in this case – but the row continues. “The flailing Harris-Walz campaign is seeking foreign influence to boost its radical message – because they know they can’t win the American people,” said Susie Wiles, co-manager of the Trump-Vance campaign. “President Trump will return strength to the White House and put America, and our people, first.”