Theresa May is discovering the power of her own logic. As a result, the chances are increasing that the UK will either stay in the EU or move into a transitional arrangement that will feel much the same as full membership.

Three months ago, the British prime minister called a general election to increase her slender majority in parliament. She said this would enable her to negotiate Brexit from a stronger position. Instead, she is now weaker, for the Conservatives lost seats in the election and May now leads a minority government propped up by the ten members of parliament (MPs) of Northern Ireland’s Democratic Unionist Party. The talk at summer parties in Westminster is that the prospects of a negotiated Brexit are receding.

One can see why by examining the four possible outcomes of the talks between the UK and the rest of the EU.

The first is that a compromise is reached along the lines that May outlined in January. These include the UK leaving the EU’s single market and customs union, regaining the power to decide which EU citizens are allowed to settle in Britain, and stopping the European Court of Justice from interfering in British decisions, yet also securing a “bold and ambitious free trade agreement with the European Union.”

This is what Boris Johnson, the foreign secretary, has called the “have cake and eat it” strategy. The UK would keep all the benefits of EU membership but none of the costs. Michel Barnier, the EU’s chief negotiator, has warned that this is impossible. There is no reason to disbelieve him, for if the UK were to secure such a deal, this would energize anti-EU sentiment in other member states.

It follows that any deal acceptable to the other EU members would fall well short of May’s stated objectives and almost certainly include a large exit fee, running to tens of billions of euros. However, the House of Commons is unlikely to approve such a deal. It would take only a handful of Conservative MPs to oppose it for the deal to be voted down. And a compromise is likely to be resisted by either strongly anti-EU or strongly pro-EU MPs. Indeed, both wings might vote against a compromise deal for opposite reasons—anti-Europeans because the deal has removed too few of the drawbacks of EU membership, pro-Europeans because the deal has removed too many of the benefits.

Had the Conservatives achieved the big majority that May had expected in June’s election, she would have had the votes in the House of Commons to defeat such a rebellion. In the event, she doesn’t. She now seems most unlikely to achieve a compromise deal that satisfies her, the other 27 member states, and a majority of MPs at Westminster.

The second possible outcome of the negotiations is that they break down. The UK would crash out of the EU in 2019 with nothing agreed on what should follow. During the election campaign, May said “no deal is better than a bad deal.” In recent days, some of the implications of a no-deal future for Britain have become clear. The UK would be ejected from European institutions that are of undoubted benefit. One is Euratom, which facilitates the supply of radioactive material vital to many cancer patients. Another casualty would be UK’s membership of Europe’s Open Skies arrangements. If the UK leaves this, nobody will be able to fly between the UK and the rest of Europe.

In both cases, one might think a side deal could be done to keep these particular arrangements in place. But both are ultimately regulated by the European Court of Justice, which May has said must play no role at all in future in the UK. There are more devil-in-the-detail nightmares that could disrupt daily life—and these are on top of the wider calamity that would afflict the UK’s economy if there is no deal.

So, if a compromise cannot be agreed, and no deal is a catastrophe to be avoided at all costs, what else could happen?

Option three is that the UK leaves the EU with none of the difficult issues resolved, and the two sides agree to keep the current day-to-day arrangements in place for a transitional period of, say, three years. Thus, the UK agrees to abide by the rules of the single market, Euratom, Open Skies, and so on, pending a future final agreement on these issues. This would require the UK to maintain free movement with the rest of the EU and to keep paying into the EU budget.

Some Conservative MPs wouldn’t like this and might vote against it. But the opposition Labour Party would be likely to either support such an outcome or abstain, because it would mean that for the transitional period, the UK’s relationship with the EU would be almost exactly what Labour proposed for the long term in its 2017 election manifesto. Labour “accepts the referendum result” but wants to keep every one of the benefits of membership.

Some MPs might argue that a no-real-change transitional phase would merely delay catastrophe, not prevent it. However, there would be nothing to stop a transitional arrangement from being extended indefinitely. The doubt is whether the EU’s 27 other member states would agree to it. If they did, then this would probably be the likeliest outcome.

But if they didn’t, or if they imposed conditions that were unacceptable to the House of Commons, option four would emerge: the UK abandons Brexit and decides to stay in the EU after all. This possibility has been talked up by many MPs privately, and by a few publicly. Sir Vince Cable, almost certain to be the new leader of the centrist Liberal Democrats, is one of them. Now, former prime minister Tony Blair has weighed in on the debate.

Politically, abandoning Brexit would delight much of the rest of the EU. If Britain’s government were to recommend this solution to MPs, most of them would support it. Although both main parties would be divided, enough Labour and Conservative MPs, along with the Liberal Democrats and the Scottish National Party, would vote for the UK’s continued membership of the EU.

The question is: How would Britain get there? May would be risking a split in the Conservative Party, not just a short-lived difference of opinion, over a single parliamentary vote. However, if neither a compromise nor a transitional arrangement is possible, then the UK will be left with a stark choice: crash out of the EU in a way that could crucify the UK’s economy and disrupt daily life to an alarming degree—or stay in the EU.

If this binary choice is the one that faces the UK in 2018, then the chances are that the polls will show a shift in public opinion away from backing Brexit and toward remaining in the EU. That would alter the dynamics of the political debate in Britain. And that is the prospect that is causing MPs across the spectrum to doubt whether the UK will ever leave the EU after all.

Peter Kellner is a journalist, political commentator, and former president of YouGov.