Although ministers will be briefed on the prime minister's important EU speech for the first time this morning, when cabinet meets, they are not coming to it completely blind.
Because last week Downing Street shared with the more senior ministers a position paper on the issues she will address.
The big unresolved question, which will almost certainly not be resolved today and would therefore be fudged in the PM's speech tomorrow, is the price the UK is prepared to pay for access to the EU market.
And when I say price I mean both money and standards imposed on UK businesses for all they make and sell, both to the EU and externally.
Because what worries those who campaigned hardest for Brexit - the Goves, Foxes and (naturellement) the Johnsons - is that the understandable ambition of the Chancellor, the Treasury and much of Whitehall to keep the UK economy deeply integrated in the EU's single market would make it impossible for UK businesses to break free of the alleged shackles of EU regulation and imposed standards.
All ministers accept of course that selling goods and services to the EU requires us to accept EU quality standards on those sales. So British made pharmaceuticals and tractors and meat pies and investment funds would still have to conform with EU imposed regulations when they are being sold to France, or Germany or any of the other 25.
But what is far more contentious is whether those same rules and standards should apply to goods and services British businesses want to sell to the rest of the world. And the more that the UK wants frictionless access to the EU - not just an absence of tariffs but an absence of border checks too - the more that the EU will demand that its standards apply to everything made in Britain.
The big and largely under-reported division in the cabinet is over the importance of securing our own power and right to set regulations and standards - or whether what matters more is maintaining the trading status quo with Europe.
This will not be decided today. And Theresa May will not settle it tomorrow.
Which means the Tories' Brexit civil war will rear its ugly head again soon enough.