It’s been a difficult year for the “special relationship” between Britain and the United States. US policymakers — including the president himself — have been struggling to set a non-patronizing tone as they nudge British voters to stay in the European Union. British politicians have struggled to respond. And then there is Donald Trump. If The Donald becomes president, his relations with the UK could be openly adversarial on a scale not seen in recent history. Last year, more than half a million Britons signed a petition to ban him from the country, forcing a non-binding debate in parliament. Mainstream British politicians — almost regardless of party — do not want to go that far. But they have also been remarkably outspoken in their opposition to the Republican frontrunner. In an interview with British television this week, Trump made it clear he took the comments personally, lambasting both Conservative Prime Minister David Cameron and new London mayor Sadiq Khan. Both had bluntly rejected Trump’s proposed suspension of Muslim migration. In many ways, this is all just political theater — and not a particularly edifying version. On both Brexit and Trump, it’s easy to argue that politicians in each country should back out from interfering in a democratic choice by another nation. There is little chance of that, however: if this year’s events show nothing else, it’s that London and Washington remain strangely fascinated with each other. Britain has always been the most emotionally invested in this dynamic. That’s why tangling with Trump will have been a big deal for Cameron or Khan. It’s unlikely Obama feels quite that way about his Brexit speech. The fact remains that the two countries interact in a remarkably unique way. If Trump should win, his dealings with Britain should be fascinating to watch. How it plays out with the UK, however, could be particularly interesting. For sure, there are clear advantages in pooling resources, particularly on military and intelligence matters. But as Iraq and Afghanistan show, that only goes so far. In Britain, particularly after it joined the US-led Iraq invasion, there is a rising feeling that the relationship became too unquestioning. British pundits talked of the desire for a “Love, Actually” moment, after the scene in the 2003 romantic comedy where Prime Minister Hugh Grant stands up against an overbearing US president. (Similar feelings helped bring down former British Prime Minister Tony Blair four years later.) This isn’t simply old-fashioned anti-Americanism. In some ways it’s quite the opposite, a visceral attachment to what happens on the other side of the Atlantic that makes everyone take it much more seriously than, say, French politics. That is exactly what is happening with Trump. Cameron and Khan, presumably, both genuinely disagree with the presumptive Republican nominee. But they also, I suspect, believe picking a fight with him is good domestic politics. A Trump presidency would almost certainly alienate many in the UK. I don’t think I’m the only Briton who started feeling strikingly more European and less Atlanticist during the second Bush presidency. But it would be intriguing if British politicians took on what seems to be a growing enthusiasm for acting as a political opposition force against the Republican candidate. That would be a new dynamic in the political relationship between the two countries — one that could produce many more “Love Actually” moments. Trump — who is, inevitably, a backer of Brexit — could simply have chosen not to respond to Khan or Cameron. But that is hardly Trump’s style. When it came to Khan, he was also being challenged by someone who was essentially the antithesis of the Trump platform — a pluralistic, moderate Muslim who, crucially, now runs London. In part, that reflects a strange paradox. As a nation state, Britain’s influence is almost undeniably slipping as other countries with larger populations and faster growing economies rise. At the same time, that process of globalization is in some ways putting London back at the center of the world. Trump’s meteoric political rise is heavily predicated on a backlash against that very globalization. His trade protectionism and anti-migrant sentiment are the polar opposites of someone like Khan. When it comes to political structures, in some ways the two countries could barely be more different. America’s Constitution is arguably an over-engineered but still incredible creation, an elaborate series of checks, balances and rules. Britain’s is unwritten, a messy swirl of evolving conventions and compromises, partisan and adversarial in a very different way. At the same time, they are indissolubly intertwined. The US system was, after all, designed by descendants of Britons who deliberately wanted to do things differently. Almost all US and British institutions, from the government and military to academia, media and business, have different idiosyncrasies yet a great degree of overlap. That’s also true in other ways. There are vast divides when it comes to social issues like religion, race, gender and gay rights. In popular culture, however, the internet and changing television habits have brought the two countries closer. When I was growing up in the 1990s, US TV series came to Britain but never went the other way. Now, UK television programs are a US staple. That brings us back to Trump. In the UK, someone like him would struggle to reach the top of frontline politics — if nothing else, he would almost certainly lack the patience to be elected to Parliament, the necessary precursor to almost all high offices. He fits a British caricature of the kind of American they don’t particularly like. Britain and America are, at the end of the day, still the two poles of the English-speaking world. What happens between them will help determine how the rest of the planet perceives traditional democracy. That may not be a comforting thought. But it need not be a disaster. Peter Apps is Reuters global affairs columnist, writing about international affairs, globalization, conflict and other issues