Empathy is a generally an underrated quality and especially so in the world of political strategy. People who enjoy gaming negotiations like to think in terms of ruthless self-interest. But when you lack empathy, that self-interest becomes harder to satisfy. Unless you understand your negotiating partner, you'll find it harder to get what you want from them.

That foundational mistake is written into every sentence of a crucial memo from No 10 special adviser Dominic Cummings and sent to the Spectator magazine on Monday night. We don't know it's him of course. It was sent by "a contact in No 10". But the length, lexicon and attitude of the writing indicates it could only ever have come from him.

The whole cultural approach of anonymising the briefing is starting to become a real problem, allowing the British government to distance itself from aggressive commentary and providing a semblance of plausibility to otherwise quite deranged commentary. The memo was from Cummings and we should say so.

Cummings's lengthy missive is angrier than the type of material put out by Theresa May's administration, but in one central area it is uncannily alike: It shows almost no understanding whatsoever of European incentives, political systems or domestic sensitivities. It is what happens when you base your negotiating posture without any empathy or interest in the other side. It's really not much more sophisticated than playing Battleships.

It starts with Leo Varadkar, who is increasingly turning into the chief villain of the piece among the hysterics on the Tory benches. The emotional origin of this newfound hatred comes from the fact that they are not used to Ireland having the upper hand against Britain. It goes against their sense of the natural order.

"Varadkar doesn't want to negotiate," Cummings insists. "He wants to gamble on a second referendum." This is pretty much the standard Brexit narrative now. The Taoiseach has strategised against Downing Street to win domestic support and is now unable to move because of his own unnecessary red lines. There is almost no recognition of the reason he has reached his position, which is that customs checks would create a poisonous combination of economic deterioration, political volatility and security targets.

The ignorance extends to the EU's position and the practical realities of what no-deal entails. "As things stand," the memo goes on, "at the end of this week they may say `OK, let's do a Northern Ireland only backstop with a time limit'."

It is quite extraordinary that Cummings believes the EU will offer this. He would not need to research very extensively to discover that it will not. It has stated it over and over again. And yet the hope still lies there, undisturbed by the most basic understanding of his negotiating partner's repeated statements.