Boris Johnson says he wants to go to the European Council in Brussels on 17 October, get a deal, get that deal ratified by Parliament, and leave the EU on 31 October. It's still possible he can do this.
The only feasible deal is the Withdrawal Agreement that has been on the table since last November.
The only feasible alteration to that deal that the Irish Government and the EU can agree to is to remove Britain from the Backstop, and revert to the original intention - a Northern Ireland-only backstop.
The outstanding question is - what else may be required to lubricate this arrangement to ease its passage through the Houses of Parliament here in SW1?
After last week’s political rollercoaster, we now know that the House of Commons as a whole does not want a no-deal Brexit, and has voted through legislation to that effect.
Talk from ministers about testing the legality of the legislation, which some over here think looks like challenging the rule of law, looks to me more like what Joe Schmidt calls "animation": off the ball moves by players designed to confuse and distract the opposition from the real intent of the play.
In this case of course, the opposition are not a rugby team but a Motley crew of Tory backbenchers, opposition parties, the media and the extra-parliamentary forces, most notably the Brexit Party.
Entertainers who perform "magic" tricks know this technique as misdirection.
The animation/misdirection is needed to get the government over the hump of the next couple of days, until the Prorogation Order is moved by the Leader of the House, Jacob Rees-Mogg. This will see the parliament shut down until mid October, just three days before the European Council.
This should give the government time to try to put together a package deal to get an amended Withdrawal Agreement past both the EU and the British parliament.
Firing 21 rebel Tory MPs (and having a 22nd remove herself over the weekend) makes the parliamentary arithmetic easier: This government is now such a minority government the ten votes of the DUP MPs are no longer enough to keep it in power: its there at the pleasure of the Tory Rebels and the opposition parties. It cannot govern in the conventional sense of the term.
It cannot even call a snap election without opposition support.
It exists to do one thing - obey the law that will be given royal assent today, the one we’ve been calling the law that bans a no-deal Brexit.
In fact that law gives the government a series of options, the first of which is to get a deal.
If it gets a deal, and the deal is approved by the House of Commons, then Brexit happens under the terms of that deal.
If it cannot get a deal, it has to ask the house if it will vote for a no-deal Brexit.
If the house declines to back either a deal or a no-deal Brexit, the prime minister has to ask the EU for an extension to the Srticle 50 deadline, and do so by 19 October (a Saturday).
That’s the point where talk of Boris Johnson resigning and a caretaker being appointed to ask for the deal comes into play.
Mr Johnson’s adamant position is he will not go back to the EU looking for more time. He will go to the EU looking for a deal.
As my colleague Tony Connelly and others have pointed out, the deal will not be done at the European Council. There is no way heads of government are going to get involved in technical treaty negotiations late on a Thursday night - this is not the same as a fisheries council.
They will want the deal pre-negotiated by the expert team they have delegated the task to, the one led by Michel Barnier.
So it is the parliamentary quiet period, following the prorogation, that is the window of opportunity. The deal must be done by 14 October, with a pretty good indication of parliamentary support for it before parliament enters a new session if it is to get the backing of the European Council.
That means the Tory rebels and the Labour Party will have to be the bulk suppliers of troops to support the government, which will lose a number of its own backbenchers (and possibly ministers) in its drive to get the deal over the line.
The Liberal Democrats have set themselves up as the anti-Brexit party, the Scottish and Welsh nationalists have their own objectives that may not allow them to back a Brexit deal at a vote.
The deal, if it can be pulled off, must be supported by a cross-party coalition if it is to come into being.
So we are back to the question we started with - what extra is needed to help get a modified Withdrawal Agreement that is acceptable to Ireland and the EU over the line in Westminster?
What might the British ask for? What might the EU side offer that goes beyond changing the backstop back to Northern Ireland only?
One suggestion is the offer of a clear way back to EU membership on current terms some time in the future (after a referendum), which might give Remainer MPs enough comfort to be able to vote for a deal that will take the UK out of the EU.
For the irony of the current state of British politics is that only Remainer MPs can deliver a deal that ensures an orderly Brexit by 31 October. And only the Remainer MPs can facilitate a no-deal Brexit too.
Either way, they will be facing the electorate before Christmas. What outcomes are most in the Irish and EU interest?
What can they do to help bring them about?