Boris Johnson has done what many thought impossible and landed a renegotiated Brexit deal with the EU.
But now comes the hard part - convincing MPs to vote for it on “super Saturday”.
HuffPost UK understands an intensive lobbying effort is underway by Downing Street and the Tory machine to get crucial factions to back the new withdrawal agreement.
Whether it’s the DUP, Tory Brexit “Spartans”, independent ex-Tories, or Labour MPs in Leave-backing seats, each group could prove crucial to Johnson’s chances of getting a deal through.
The DUP
Who are they? The unionist Northern Irish party’s 10 MPs have helped prop up the Tory minority government since the 2017 snap election.
What’s their current position? Not backing the deal.
They object to the deal’s introduction of customs checks between Northern Ireland and Great Britain to keep the border with the Republic of Ireland invisible, arguing it would increase costs for Northern Irish businesses.
Perhaps more fundamentally, the party also said the deal “drives a coach and horses” through the Good Friday Agreement, which says Northern Ireland should be governed with the consent of both unionists and nationalists.
By contrast, the deal allows the trade arrangements to be approved by a simple majority at Stormont, which the DUP argues would allow nationalists to impose the measures on unionists.
Could they be persuaded? The government is still straining every sinew to get the DUP over the line and talks are ongoing.
But given the fundamental nature of their complaints, it seems unlikely.
What does it mean? Throughout the Brexit process so far, the group of around 30 hold-out Tory Brexit Spartans in the European Research Group (ERG) have acted in lockstep with the DUP. If that continues, the combination could prove fatal for Jonhson’s deal.
The ERG Spartans
Who are they? Led by self-anointed “Brexit hard man” Steve Baker, the hardline Eurosceptics of the ERG were called “bastards”, Taliban, and everything else in between while scuppering Theresa May’s deal and premiership.
Some peeled away as May held three meaningful votes on her deal, but 28 still opposed it on her last attempt on March 29.
What’s their current position? Unknown.
Baker and others were waiting for legal text before making a decision, and they will now be going through it in detail, including taking legal advice.
They may have concerns about the re-emergence of so-called level playing field provisions, which would mean the UK could not undercut EU rules in areas like workers’ rights, environmental protections, state aid and so on.
But these have been moved from the binding withdrawal agreement to the non-binding political declaration, suggesting that issue is still up for grabs.
Moreover, the dreaded Irish border backstop has been dropped, a key demand.
And they trust Johnson when he says he wants a loose free trade deal with the EU to give the UK more control of its own affairs - and the ERG a harder Brexit than that proposed by May.
Could they be persuaded? For the first time in the Brexit process there is a genuine sense that the ERG-DUP alliance might be broken.
Baker and other key figures such as Mark Francois attended rolling meetings with government figures as Downing Street tried to keep them in the loop as concessions were made in negotiations.
But there have been rumblings of discontent from the likes of Iain Duncan Smith and Owen Paterson, who do not want to sell out the DUP.
What does it mean? Without most of these MPs on side, Johnson stands little chance of getting a deal through.
Sacked Tory Brexit rebels
Who are they? Johnson sacked 21 MPs from the party, including the likes of Philip Hammond, Rory Stewart and Ken Clarke, for backing the so-called Benn act to block a no-deal Brexit.
Most of them supported May’s deal, while a handful are ardent Remainers who will never vote for any deal.
What’s their current position? Hammond made clear on Thursday that he does not want to back a deal which could allow the Tories to turn Britain into a US or Singapore-style ultra-free market economy.
The ex-chancellor even went as far as accusing Johnson of surrounding himself with people inspired by US Republicans and “neocons”.
But most want to get Brexit delivered with a withdrawal agreement, to avoid a cliff edge no deal situation.
Could they be persuaded? Around 16 are thought to be in play for backing Johnson’s deal, and appear likely to do so due to their desire to deliver Brexit.
They may also be motivated by the possibility of being readmitted to the Tories in time for the next election.
But the likes of Hammond may be past the point of no return.
What does it mean? They are unlikely to act as a bloc but like every other faction in this group, most of them will have to back the deal for it to pass.
Labour MPs in Leave-voting areas
Who are they? A group of 19 Labour MPs wrote to European Commission President Jean Claude Juncker last week making clear they want to see the Brexit vote “honoured without further delay”.
They include the likes of Caroline Flint, Stephen Kinnock and South Yorkshire mayor Dan Jarvis.
What’s their current position? Kevin Barron, who is standing down at the next election, has confirmed he is backing the deal.
But the rest are keeping their counsel and studying the legal text.
Gloria De Piero said before the deal was done that the more details that emerged about it, “the less likely I am to vote for it”.
The group want to build on concessions given by May in cross-party talks - including the protection of workers’ rights and environmental standards, and a role for parliament in the next stage of negotiations.
Johnson has kept open the channels of communication but appears less willing to to offer such compromises, as he pursues a harder Brexit to satisfy the ERG MPs who put him in Number 10.
The shift of level playing field provisions from the legally binding withdrawal agreement to the non-binding political declaration will be causing concern.
Could they be persuaded? It will be a hard sell for Johnson to get these MPs to back an arguably more “Tory” Brexit than May’s deal.
That said, they will have to weigh up the concerns of their Leave-voting constituents who are simply desperate to get Brexit done.
On the other side of the coin, Jeremy Corbyn could yet threaten to sack them from the party to keep them in line.
What does it mean? This group could make or break the deal, depending on what happens in other factions.
Johnson may be in business if 10-15 row in behind. Fewer than that and it begins to look difficult.