So she's only gone and done the deal. There will be no "hard border" with Ireland, and EU citizens in the UK – and UK citizens in the EU – will see their rights protected. The so-called "divorce bill" will amount to between £35 billion and £39 billion. Jean-Claude Juncker has referred to it as "sufficient progress", while Donald Tusk described it as a "personal success" for the PM. But should Theresa breathe a sigh of relief just yet?
Despite her apparent successes last week, May is still trying to reconcile the irreconcilable – the demands of Brexiteers and Remainers, the SNP and the DUP – and fight off a threat from Labour.
She has been kept in office by three things: one, her party can’t agree on a preferred successor. Two: if she goes, the already compressed timetable for the Brexit negotiations is likely to be further shortened while a leadership contest takes place. And three: there would be strong pressures to have a general election, which a Corbyn-led Labour party might win. So, as we move on to the next stage of Brexit negotiations, who is most likely to be a thorn in May's side?
The PM has faced major problems here. It was the DUP whose opposition to a potential Irish border agreement last Monday led to talks breaking down, and May depends on the party's support to win key votes in Westminster. Relations have certainly improved, though they are saying there is still "more work to be done" on the border issue, and that how they vote on the final deal "will depend on its contents".
The whole debacle over this deal that was, and then was not, shows the weakness of a government reliant on the ten DUP members. "One almost has to feel sympathy for her predicament," says Iain Begg, Professorial Research Fellow at the European Institute at the LSE. "But it is a predicament for which she bears considerable responsibility."
Others agree. Tim Bale, Professor of Politics at Queen Mary, University of London, thinks that what happened last week was one of the most predictable accidents waiting to happen that he’s seen in decades of studying politics for a living.
Likelihood of bringing down the government? Moderate. The DUP have shown they're willing to screen May's calls and need to prove to their base that they’ve not caved in. May needs them just as much as ever.
Brexiteers in her own party
Generally, zealous Tory Brexiteers are a massive pain for May. But judging by the supportive response to last week's deal from colleagues on social media, May seems to be back in their good books. Priti Patel described it as an "important step forward" and James Cleverly called it "the Brexit we voted for".
Neverthless, Adam Drummond, head of polling at Opinium, thinks it's these guys who pose the real problem for May. "What Brexit-supporting Tory backbenchers find acceptable is quite different to the average Leave voter," he says. "There is a possible Brexit deal that’s acceptable to a majority of the population whereby Britain continues to follow EU single market rules and pays into the EU budget in exchange for greater control over immigration." He points out that this is an outcome that the bulk of Leave voters (54 percent) and Remain voters (62 percent) would find acceptable, but that it fails the "sovereignty first" test that motivated committed Leavers like those currently in the Cabinet and on the Tory backbenches.
However, luckily for May, there aren't that many of them. "Most Conservatives who wanted to leave or who’ve reconciled themselves to it will probably accept sort of compromise as long as they can claim in 2019 that the UK has formally left," says Bale.
Likelihood of bringing down the government? Severe. These guys may seem chirpy today, but they're hellbent on getting the Brexit they want, no matter what this means for May or Britain.
Remainers in her own party
After 18 months of dithering, these guys are just pleased to have made some progress. For months now, Conservative Remainers might have been thinking and even saying 'I told you so' in private, but the vast bulk of them – and there are more of them, still, on the Tory benches than there are Leavers – are still very reluctant to make their doubts public, let alone vote against their government. Certainly, May now has some much-needed breathing space. As a result, unless the Remainers "show some guts and start barking and then biting, May will carry on in thrall to the Brexiteers" because they are the ones most likely to bring her down, says Bale.
Plus, as Drummond points out, most of the "mutineers" have been reliably supporting the government when it comes to key votes.
Likelihood of bringing down the government? Low. The majority of Tory party members are also Brexiteers, and MPs need to keep them happy if they want to keep their seats.
Nicola Sturgeon may already be "banging the Indi drum", as Ruth Davidson says, but how will the latest developments impact Scotland? Here, there are two things worth remembering. One is that the 13 Scottish Conservative MPs contribute more to Theresa May’s overall majority than the 10 DUP MPs. "It's a question of how rebellious they feel, but it’s hard to see them threatening to bring down the government in the way that a break with the DUP might," says Drummond. Secondly, Scotland voted Remain. "Ruth Davidson is running to be first minister of Scotland rather than leader of the Conservative party at a UK level, so she’s not running as much of a risk advocating a softer Brexit as someone like Philip Hammond or Amber Rudd might," he adds.
If the idea of territorially separate deals gains any more traction, this will make things uncomfortable for Davidson as it would chime with SNP demands.
Likelihood of bringing down the government: Moderate. With the Tories void of any talent or popular figures, the well-liked Scottish leader could be a threat.
The Shadow Secretary of State for Brexit, Keir Starmer, has been keen to point out that May needs to rethink her approach. "Another year of chaos and confusion" is not acceptable, he says. But what about their tactics? Labour is either playing a very clever long game, making sure they don’t run too far ahead of public opinion, but gradually undermining hard Brexit, or making it up as they go along. Who knows what they really want. A Norway-style agreement? The wholesale reversal of Brexit?
Drummond reckons Labour’s position on Brexit this last year has been one of "masterful ambiguity", and they’re doing the most sensible thing electorally by maintaining this. He points out that most Labour members, voters and MPs voted Remain, and in the general election the party sucked up votes from those opposed to Brexit, but by making it clear that they wouldn’t stop Brexit, Leave voters not inclined to vote for the Tories also felt safe voting Labour. "The party has many internal contradictions on Brexit, and their best bet is to be a Rorschach blot for everyone dissatisfied with the government’s handling of Brexit, rather than spelling out their alternative unless absolutely forced to do so," he says.
Likelihood of bringing down the government? Moderate. They might not know what they really want, but they do know that they need to steer clear of being accused by their constituents of defying the supposedly sacred "will of the people".