All prime ministers run the risk of hubris, the Downing Street historian Anthony Seldon observed in a lecture on Tuesday. David Cameron’s fall is the most recent illustration of that. Mr Cameron thought he could win a referendum on the European Union and marginalise Ukip. He failed, with disastrous consequences for Britain. Theresa May is the beneficiary. But Mrs May is now running the same risk, of thinking that she can hold on to power and popularity by tacking to the right and trying to squeeze the air out of Ukip.

Mrs May’s policy on Brexit is at the heart of this recklessness. Mrs May thinks she must sacrifice UK economic confidence and national interest in favour of control of borders and migration. This is wrong enough in itself, as Kenneth Clarke pointed out in his formidable contribution to Tuesday’s Commons debate. This is also why opposition MPs should join him to oppose Mrs May’s bill to trigger the UK’s departure from the EU.

But this foolish choice of priorities also pushes the May government into the premature embrace of a trade deal with the United States, which now means with Donald Trump. Brexit activists welcomed Mr Trump’s win. But his presidency is changing the already severe risks from Brexit into something potentially disastrous for Britain.

Mrs May heads a government that is committed to free trade; Mr Trump is the most protectionist president of modern times. Mrs May supports the United Nations and Nato; Mr Trump is equivocal, at best, about both. Mrs May says she wants the European Union to succeed; Mr Trump gives every indication of actively seeking the EU’s collapse. Mrs May supports the Iran nuclear deal; Mr Trump aims to withdraw from it. Mrs May is firm about sanctions against Russian aggression in Crimea. Mr Trump hints constantly that he wants the sanctions lifted.

Mrs May did not spot the dangers of all this clearly enough at first. Instead she was goaded by Nigel Farage’s early access to Mr Trump, and by the suggestion that the former Ukip leader might be a suitable UK ambassador to the US, to try to push Mr Farage to the margins. Doing down Mr Farage weighed more heavily than advancing the UK national interest. So she did something he could not, prematurely offering Mr Trump a state visit to the UK, with all the access to the Queen and the accompanying pageantry that the US president could want.

This offer may have seemed smart when it was decided within a couple of weeks of Mr Trump’s election. But it has now proved to be a disaster two weeks after he took office. The practical problem for Mrs May is stark. Mr Trump cannot now come without London becoming a battleground and the visit a huge embarrassment to the Queen. Somehow or other, it must be postponed or abandoned.

That’s because moderate as well as radical opinion in the US and Britain has been scandalised by the sheer nastiness of Mr Trump’s early moves. Even the Brexiters have now gone quiet about him. The most dangerous global effect of Mr Trump’s acts is to be a recruiting sergeant for radical Islamists. That’s difficult enough for Mrs May. But her hope of promoting her Brexit policy by posing as a firm and practical ally of Mr Trump now isn’t working in middle Britain either. It may even provide the missing ingredient that the SNP is constantly searching for to prise Scotland out of the UK.

Mrs May’s Brexit strategy is in crisis. The approach was already bad enough – pushing ahead with Brexit too fast, hardening the terms, threatening a tax and tariff war with the EU if she doesn’t get the deal she wants. All of this was shaped by the old Tory instinct for playing to the Eurosceptic gallery. But now it is worse still. She is aiming for a theatrical snub of the EU by triggering article 50 at a summit on 9 March, just six days before the Dutch general election, thereby actively helping the anti-EU and anti-migrant Freedom party of Geert Wilders.

Even this, though, could be as nothing compared with the perception in Europe that Mrs May’s Britain is happy to work to undermine and even destroy the EU in alliance with Mr Trump. That is becoming a real possibility. It is an outcome that even Mrs May must want to prevent. It would mean the UK getting not the best of both worlds in its relationship with Europe and the US, but the worst. A collapse of relations with Europe alongside an “America first” trade deal with the US is a nightmare scenario. But Mrs May’s policies have made it a real possibility. MPs who are uncertain which way to vote on article 50 in parliament on Wednesday should get real and vote to stop this madness.