Leaving the EU is uncannily like being in the EU - characterised and degraded by a chronic absence of trust on both sides.
The casualty this time looks set to be the PM - who has gone to the Netherlands and then Berlin and Brussels - to urge EU leaders to give her some words that will prove to her critics in Parliament that the backstop they hate will not be forever.
Her chances of success are similar to mine if I were to ascend the south face of K2 in flip-flops.
What May is likely to be offered, at best, according to sources in European capitals, is “interpretative statements to the Withdrawal Agreement [which enshrines the backstop]”.
They will have “legal value” but “they cannot change or contradict the Withdrawal Agreement”.
Even for the EU 27 to do that, EU leaders would have to know what “interpretation” would actually secure a majority for Theresa May as and when she finally puts the Brexit plan to a Commons vote.
And here is the authentic voice of scepticism that any of this is more than fatuous displacement activity on a geopolitical scale.
“As TM has not tested the deal [in a vote of MPs], there is no way of knowing what could work”, said an official from an influential government. “Seriously, I don’t think even a Withdrawal Agreement without a backstop would pass."
What is utterly certain - as Northern Ireland’s DUP and Tory Brexiters have said with zero ambiguity or wriggle room - is that a majority of MPs will vote against her Brexit plan unless the Withdrawal Agreement is renegotiated to put a formal end date or exit mechanism controlled by the UK on and in the backstop.
NONE OF THAT WILL HAPPEN.
In fact the backstop will not be reworked in any way.
To labour the point, statements interpreting the true meaning of the backstop by EU leaders will not cut it for the DUP or Brexiters, because the Withdrawal Agreement always overrides such interpretation in a formal legal sense.
So the best the PM can hope for is that whatever amicable statement she secures from the EU27 this week will persuade a few of her less ideological critics to back her.
The most she can hope for is that when the meaningful vote finally takes place, she will lose less meaningfully - with a smaller margin - than would have been the case today.
She knows that. And presumably thinks it is worth it to lose five-nil rather than 10-nil.
And if the rest of us are bemused why that matters to her, I doubt she will put us out of our misery.