The Guardian view on Trump’s visit is that it was doomed from the start, because he doesn’t want what Britain wants.

The president undermined Mrs May before he even left America. He bullied and lied at the Nato summit in Brussels. He then gave an explosive and deliberately destabilising interview to Rupert Murdoch’s Sun on the very day of his arrival in Britain.

Deliberately. I don’t know. Maybe, but maybe it was just more loosely Trump’s unerring taste for the mean and vulgar.

But it was not just the rudeness that mattered – though rudeness does matter, a lot, both in personal and in public things. It was the political impact and consequence. That unmistakable consequence is that Mr Trump’s America can no longer be regarded with certainty as a reliable ally for European nations committed to the defence of liberal democracy. That is an epochal change for Britain and for Europe.

Well Trump’s America never could. If anybody said in January 2017 that America could still be regarded with certainty as a reliable ally for European nations committed to the defence of liberal democracy, anybody wasn’t paying attention. Certainty on that question wasn’t reasonable even then.

The Guardian says Theresa May was that anybody.

Everything about this disastrous and embarrassing presidential visit could have been avoided with more thought and more political sense. But Mrs May and her advisers rushed to Washington in January 2017 to offer a state visit to a president who had barely entered the White House, whose measure as an ally they had not yet properly taken, but who already had it in his character and his power to transform the event from a relatively harmless occasion into a deeply wounding one. It was a shameful and stupid misjudgment. The hostile public reaction was immediate and without precedent. Everything that has happened this week confirms that the Trump visit should not have taken place.

Indeed. We said so at the time. “Why is she all over him like a cheap suit?” we said.

Mrs May should have grasped from the very start that Mr Trump was not an ally when it came to her Brexit strategy. Mr Trump wants to break up international organisations like Nato and the EU. He embraced Brexit on that basis. He saw it as the start of a swing back towards nativist, illiberal, often racist nationalist politics, of which his own election was a further example. He made no secret of his wish to promote other nativist movements on the right. Other European leaders understood this danger, notably Angela Merkel. Mrs May failed to do so. Mrs May rightly wanted a close post-Brexit relationship with the EU, a stance that led in time to the Chequers showdown with her Brexiteer ministers a week ago. But she failed to see that Mr Trump’s US has a stronger commitment to the weakening of the EU than it does to a Britain that wants the EU to prosper.

Out of that failure came the Sun interview. In the interview, Mr Trump expressed hatred for the EU, support for hard Brexit, unwillingness to strike a trade deal with the UK, contempt for Mrs May, support for Boris Johnson, hostility to immigration, and offered his barely coded belief that the UK – and Europe – is “losing your culture”. The interview, its content, its timing, and the fact that it was given to Mr Murdoch’s flagship anti-EU tabloid, was a deliberate hostile act. For Mrs May, fighting to control her party on the dominant issue facing Britain, it was simply a stab in the back. But it wasn’t fundamentally personal. It was a declaration of hostility to Britain and Europe and the values they stand for.

I remain agnostic about how deliberate it was…if only because nothing Trump does is really all that deliberate. He does what he likes to do, and he likes doing things like outraging other heads of governments and doubly so if they’re women, and embracing racism, and trolling liberals.