It was all going so well. The UK Prime Minister had secured the honour of being the first foreign leader to meet the new President of the United States.
The visit appeared to be a success, the joint press conference ensued without any of the off-script tirades that had been feared, and the iconic shot from the trip was the President clutching the Prime Ministers hand for support.
Brits breathed a cautious sigh of relief: he might have run an unconventional campaign, but maybe this was a leader the UK could work with after all.
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Here we are 18 months later, and while Trump is no longer leaning on May for physical support, he is still putting an undue amount of pressure on her – and the rest of the world.
Forget the protests for a moment. Forget the giant baby inflatable due to float over London. Forget Trump wading in over British politics on the eve of his visit, accusing the UK of being in turmoil and declaring “Brexit is Brexit” with no indication that he has any clearer idea of what that means than the rest of us do.
Forget his retweeting of racist posts by hate-group Britain First, his Fox-fuelled lies about knife crime and radical Islam in the UK, and his ongoing feud with London mayor Sadiq Khan.
Focus too hard on any of the above, and you miss the very real way that Trump is breaking the rules that govern the world.
Since the shock announcement of the travel ban on foreigners from seven mainly-Muslim countries, Trump has spurned every norm and expectation that those familiar with global politics took for granted.
Lets start with his hardline stance on undocumented immigrants coming to the US from Mexico, and the humanitarian crisis it has caused at the border. Some 3,000 crying children – more than 100 under five years old – have been torn away from their parents.
In this, Trump has brought condemnation and fury on America from the rest of the developed world, and irreversibly damaged any sense that the US can be a leader in human rights.
Looking outwards, Trumps obsession with US protectionism has sparked the trade war that economists feared, in violation of WTO rules.
Launched on dubious “national security” grounds, it has done irreparable harm to relations with key US allies. The escalation of tariffs is estimated to cut international trade by four per cent – and wipe $800bn off global GDP.
On multilateral alliances like the G7 and Nato, he has shown nothing but disinterest or disrespect.
In particular, note his comments last month that Russia should be allowed back into the G7/8, with no appreciation either of the circumstances that led to its expulsion (namely, annexing Crimea), or of the fact that two people had just been poisoned with a deadly nerve agent on British soil, in an attack widely accepted to be the work of the Russian state.
In fact, at every turn, this President has alienated traditional American allies, in favour of cosying up to Vladimir Putin. It was no surprise earlier this week when he joked that his meeting with the Russian President would be the “easiest of them all” on his European tour.
Which, of course, brings us to the murky web of connections and collusion between members of the Trump team and shadowy figures in the Kremlin. This isnt hyperbole or conspiracy theory – four former Trump associates have already been charged by the FBI.
The Presidents response, aside from firing the last FBI director and calling for the investigation to be shut down, has been to muse on whether he can legally pardon himself.
This contempt matters. Global influence – be it through trade agreements, supranational bodies, or simply implicit understandings of cooperation and soft power – takes years to build.
We are in the process of finding out how quickly it can be destroyed.
It is hard to see how the next US President, whoever they are, can undo the damage that this one has already done not only to Americas reputation, but to the codes and conventions that have governed the developed world for three quarters of a century.
Maybe the status quo needed shaking up. Perhaps one-to-one relations are more appropriate today than sweeping multilateral organisations, and its possible that traditional alliances based on history and geography dont make as much sense in our globalised world as they once did.
But with Trump in the UK today, this is a paradigm shift Britain cannot afford to ignore. We cant work with the President – no one can, not even his own team. And we will struggle to trust the US to be a leader, economically or socially, regardless of the size of its military
Instead, Britain needs to be preparing for a world that is no longer deeply underpinned by US-led soft power. Itll be a damn sight harder than flying an inflatable Trump baby over London, but its the only way we can stay relevant in a future that will certainly not be led by America first.