Why everyone but May hates her backstop
Every government Brexit policy is seen through the prism of betrayal by Tory MPs, of both Leave-y and Remain-y persuasion, which is why objective scrutiny of them is so rare.
But I've made the categorical error of trying to read the government's "technical note: temporary customs arrangement" through my normal spectacles.
And it strikes me that its publication could have weightier implications than whether the Brexit minister stays or goes - hefty as that might be.
Because if ultimately the Tory Party and the EU were to accept this so-called backstop to keep open the Ireland border, then it would represent an important model for the UK's future trading relationship with the EU.
What is striking about the plan is that it covers the parts of the customs union and single market necessary for costless, frictionless trade with the EU - but without the obligation to continue with free movement of people.
It would give the UK regulatory autonomy over 80% of the UK economy, the part represented by services and not goods or food, and would curtail (though not eliminate) the sway of the European Court of Justice.
It represents the legendary "having of caking and eating of said cake". What's not to like, Boris Johnson?
Which is why some would say the True Brexiters, like Davis and Johnson, are certifiably bonkers to make it life-or-death that there is an end date for the arrangement.
The captains of multinational industry would die to have the backstop as a permanent frontstop.
But it is also why, as it happens, I assume the rest of the EU will reject it - because it would be an incredible breach of their religious belief that the rules of the customs union and single market should be the same for all (and yes, I know they were prepared to make an exception for Northern Ireland alone - but that's because Northern Ireland is not an independent country, and the maintenance of peace is so important). This backstop can't be offered to the UK, because eurosceptics and populists all over the EU would see it as superior to EU membership.
Or to put it another way, the reaction to the backstop at the EU summit in a few weeks will tell us something that will be momentous for those businesses which have a choice about which country they invest and employ: if it is rejected, as it probably will be, then they might as well surrender all hope that May will give them easy access to their biggest market, the EU's single market.
And they may well then vote - even more than they are at the moment - with their wallets, to the detriment of the UK.