Just a day after declaring her cabinet united behind her in pursuing a new Brexit plan, UK prime minister Theresa May stands on the brink of political oblivion. Four of her cabinet ministers resigned today, including Brexit secretary Dominic Raab, setting up a very difficult vote in Parliament over the plan:

The morning after the night before was a rough one for British Prime Minister Theresa May. On Wednesday night, she announced that she’d won her cabinet’s backing for her draft proposal on how the U.K. should pull out of the European Union. On Thursday morning, May’s Brexit secretary, the man who led her negotiating team in Brussels to hammer out that draft, quit, along with another member of her cabinet and several junior ministers.

Dominic Raab, the second of May’s Brexit secretaries to quit the role in as many years, said the draft agreement reached with Brussels would effectively leave Britain beholden to the rules and regulations of the European Union and even give the EU the power to stop the U.K. from extricating itself down the road. He said he could not “in good conscious support the terms” of the deal he helped to craft.

Raab wasn’t the only member of May’s government to walk out on Thursday. Her Junior Northern Ireland minister Shailesh Vara, junior Brexit minister Suella Braverman, and parliamentary private secretary Anne-Marie Trevelyan also stepped down.

Prospects for approval for May’s draft agreement look slim — and chances it will come to a vote at all are less than solid, too. May could well face a vote of no confidence before Parliament even gets a chance to consider the draft agreement:

That may be a little premature, according to Sky News reporter Kate McCann:

Still, Rees-Mogg pointed out what he clearly sees as May’s failings in the agreement and asks, “Should I not write to my right honourable friend, the member for Altringham, and sail west?”

This has some parallels to the Nancy Pelosi leadership fight in the US. There seem to be a number of Tories unhappy with May, but not too many people ready to challenge for leadership, even among the hardline Brexiters. Raab insisted that he wants May to remain in place:

I think she needs a Brexit secretary that will pursue the deal that she wants to put to the country with conviction. I don’t feel I can do that in good conscience. But I respect her, I hold her in high esteem, I think she should continue, but I do think we need to change course on Brexit.

The issues created by the draft agreement go well beyond resigning ministers. After having reviewed the draft agreement, Scotland’s first minister declared that it would result in a new and successful Scottish independence vote:

It was “reasonable” to think that the timing of a possible new vote on secession would depend on how Britain’s current political chaos over Brexit played out, she told Scotland’s devolved parliament.

“That time will come, and when it does I have no doubt that the people of Scotland will choose to be independent,” she said.

Sturgeon and others in the Scots parliament were angered by terms in the agreement that they claim benefit Northern Ireland at their expense. “This is not an academic or abstract argument,” Sturgeon declared, “but has real consequences for jobs and living standards in Scotland.” She also called for David Mundell to resign from May’s cabinet, as he had promised to do in a letter to the leader of the Scottish Conservative Party weeks earlier if a deal emerged that “threatened the integrity of the UK’s internal market.”

May gamely tried selling the plan to a skeptical Commons, but ended up admitting that the deal could lock the entire UK into the backstop EU customs-union arrangement for the foreseeable future. The problem, May said, is that this is the best deal that could be arranged — and the only deal that gets the UK back its territorial sovereignty:

Theresa May has admitted she “shares concerns” that the UK could be locked into the backstop arrangement, amid testy exchanges in the House of Commons following the departure of two cabinet ministers. …

Iain Duncan Smith, the former Tory leader, said he had serious misgivings about the backstop, saying the UK maintained the “sovereign right to leave bodies like Nato and the UN” but would not have that right over the backstop arrangement.

In her reply to Smith, May accepted that coming out of the backstop would require mutual consent. “I won’t make any bones about that,” she said.

“Across the house there are concerns in relations to the backstop and I share some of their concerns, these have not been easy decisions to take. It has been necessary and would be necessary in any deal we were striking.”

It looks like the Tories won’t be satisfied with just control over immigration. If May presses ahead with this deal, the Tories might turn to new leadership with more hardline Brexit views, which will likely produce a crash-out of the EU and a hard border in Ireland.