By the end of the summer, Keir Starmer had led the Labour Party to a dominant election win to become Britain’s new prime minister, and Donald Trump was looking like an even bet to reclaim the White House. As I suggested in February, Trump and Starmer could hardly be more different in politics, personality or attitude — the Barnum-like cult leader, focused on power, cut a sharp contrast with the stiffly pious public prosecutor. There have been several awkward stumbles in the relationship between the once-and-future president and his British counterpart. Starmer’s foreign secretary, David Lammy, has been furiously backtracking on a record of social media denunciations of Trump: a “tyrant in a toupée,” “a racist KKK and Nazi sympathizer” and a “woman-hating neo-Nazi-sympathizing sociopath” are among his punchier insults. Starmer himself is on record describing the president’s views as “absolutely repugnant,” and he once tweeted, “Humanity and dignity. Two words not understood by President Trump.” A difficult situation got worse last month, when the Trump campaign filed a complaint with the Federal Election Commission, accusing the Labour Party of “blatant foreign interference” in the presidential race for organizing volunteers to help the Harris-Walz campaign. It was as much a political gambit as a sober legal challenge, but it seemed to reveal genuine irritation and offense on the part of Trump and his closest advisers. It goes without saying that Starmer would have preferred Vice President Kamala Harris to have won. They are both left-of-center lawyers from progressive political parties. The prime minister is not alone in feeling surprise at the apparent scale of Trump’s victory, with the prospect of the Republican Party also taking control of the Senate and retaining a slender grip on the House. But Starmer is also a grown-up and he has to accept reality. That means playing the hand he has been dealt. Intemperate remarks from the past cannot be undone, and the internet never forgets. But it is difficult to know how much they will matter. After all, Vice President-elect JD Vance once called Trump “reprehensible” and a “moral disaster.” Trump will evidently forgive transgressions by those who submit and abase themselves before him. At the same time, Trump has paper-thin skin and is known not to distinguish between the political and the personal. Grievances are not time-limited. The fantasy that he won the 2020 election and it was stolen from him has become an article of faith. Last week, the newly elected Conservative Party leader, Kemi Badenoch, put Starmer on the spot by asking whether Trump would be invited to address Parliament as part of a state visit to the U.K. The prime minister ducked the question, aware of its hidden weight. In his first term, Trump made two state visits to the U.K., in 2018 and 2019, and on both occasions the opportunity to speak to both Houses of Parliament was blocked by former speaker of the House of Commons John Bercow. Badenoch was throwing a punch, but she had a point. It was 18 months into his presidency that Trump made his first trip to Britain, the 17th country to host him. That cannot happen again. There are rumors, albeit from the mercurial Trump cheerleader Nigel Farage, that an invitation to the new president has already been agreed. In any event, it should be at the top of the British government’s agenda. Their welcome should be early, extensive and effusive. Politics is not a matter of socializing with those who share your views and values, but about promoting the national interest. Whether Trump or Harris had won last week’s election, the U.S. remains Britain’s most important ally and partner. The bilateral relationship, however “special” it may or may not be, is central to British foreign policy. No prime minister is expected to pay homage to the American president like a knight to his feudal lord, but the reality is that Britain is the junior partner, and benefits more from the relationship with the U.S. working well. The agenda is groaning. The U.K. sorely needs a free-trade agreement with America, which goes against Trump’s instincts, although he allowed negotiations to begin in March 2020. Starmer will seek to persuade the returning president that Ukraine and NATO are both causes worth supporting, despite his inclinations. And suggestions that Washington could withhold intelligence from the U.K. must be headed off. None of this will be achieved by righteous bellowing from the sidelines. If Britain is to maximize its long relationship with America, it will only do so by pulling Trump 2.0 close and offering the warmest welcome it can. Starmer does not need to mean it, but it is essential that he is seen to mean it. Eliot Wilson is a freelance writer on politics and international affairs and the co-founder of Pivot Point Group. He was senior official in the U.K. House of Commons from 2005 to 2016, including serving as a clerk of the Defence Committee and secretary of the U.K. delegation to the NATO Parliamentary Assembly.