Unhindered by the standard logic of decision-making, Trump involves himself in Brexit

For Trump the politician, the success of the Brexit project would ring-fence his anti-migration, anti-globalisation philosophy, writes Damien McElroy

Former UK Foreign Secretary Boris Johnson and Brexit minister David Davis watch Prime Minister Theresa May speaking at the Conservative Party Conference last October. Both resigned last week sparking a crisis for Mrs May. Facundo Arrizabalaga / EPAShow less

No one could ever accuse Donald Trump of using so-called "decision tree logic" when fashioning his policies.

Rather, the US president sets out the horizon of his choosing and hopes to force others to fall in line.

As is now obvious, Mr Trump abides by the rules of The Art of the Deal. Barge into a situation, set out the maximalist offer and harry the other side until more than was ever possible is on offer.

Alternatively if his counterpart is an awkward character prone to loitering in the shallows – think Kim Jong-un and others – flatter them until they are standing in the sunshine offering a handshake.

How this approach performs with Russian President Vladimir Putin at the summit in Helsinki on Monday is anybody's guess. After a week in Europe, it is clear the president's methods are blindsiding the continent.

After hurling grenades at UK Prime Minister Theresa May during a three-day visit to Britain, Mr Trump demonstrated that he sees Brexit as a key platform for his new world order.

We can now list Brexit alongside Jared Kushner’s Middle East peace effort, Iran sanctions, the Chinese trade battle and the Mexican wall as achievables in the eyes of this president.

The realisation that Mr Trump is a player not an observer in Brexit is consequential, not least for the Europeans.

The closing press conference at the Nato summit saw Mr Trump declare victory, in spite of the fact that none of the countries had agreed to his sudden demand that states spend four per cent of GDP on defence.

The penny dropped, after an emergency session, that the existing two per cent goal had better be met sooner rather than later. Hence Mr Trump was ready to declare himself the winner.

What merit exists in Mr Trump’s methods is the most hotly contested issued of the day. And Brexit offers a fascinating test for the "America First" president.

With a Scottish mother and golf course properties dotted throughout the British Isles, the 72-year old is a vanishing breed of American who sees a bit of himself in the old country.

And for Trump the politician, the success of the Brexit project would ring-fence his anti-migration, anti-globalisation philosophy.

Globalisation saw the smooth erasure of borders at the turn of the century, but Brexit could truly be a starting point to build a new world order.

However, the recent turmoil surrounding Brexit has offered an insight into an alternative mindset – one that diverges considerably from Mr Trump's. The fate of the UK Brexit secretary, David Davis, who dramatically quit on Sunday night initiating a crisis for Mrs May, is a case in point.

Mr Davis is a devotee of decision tree logic, the tendency to think through the various consequences of given actions. In the case of Mr Davis, Mrs May’s recent Brexit decisions brought into question his ability to deliver his most cherished goal – a clear break in Britain's link with the European Union.

To put it simply, Britain could either tear up every established link it has with Europe or find a compromise.

In quitting, Mr Davis recognised he did not have the intellectual skills or desire to engineer a new hybrid model.

So the man charged with delivering Brexit gave up because he did not believe he could deliver an outcome that would be satisfactory to himself.

If Mr Trump used these methods he would never embark on the tangents he fires off on an almost daily basis.

A logic tree would provide no route for Mr Trump to decide to meet with Mr Putin on Monday. The range of possible outcomes at each stage would point away from taking the risk of outreach.

But as we have come to understand, the US president does business differently from the statecraft practiced at the diplomatic top table for a generation. At one level he makes open-ended punts; having pushed his respondents back on their heels, he can then decide if their response gives him something to play with and capitalise on.

At another level he seeks to bait those offering nothing where he see the potential for a big breakthrough.

At the Nato summit he was asked what his perfect game plan resembled.

“What would be the ultimate?” he queried. “Well, let's see. No more nuclear weapons anywhere in the world would be the ultimate, okay. No more wars. No more problems. No more conflict. Let's find a cure to every disease known to mankind, or womankind. That would be my ultimate, okay, and we'll start from there.”

The point about Mr Trump is that he is not a mystery. He pursues exactly the outlandish promises he makes. It’s just that the rest of the world takes too long to catch up.