Three years after the United Kingdom voted to leave the European Union and two weeks after it was supposed to have left, Prime Minister Theresa May returned to Europe this week, hat in hand, to ask for a second, last-minute extension. Hanging in the balance were Britain’s access to certain food and medicine, the stability of its financial markets, and peace at the Irish border—all of which would be threatened were the U.K. forced to exit the EU with no deal in place.

Late Wednesday, the EU offered not the short-term extension May had sought, but a six-month delay. Through the revised timeframe, a second referendum and a general election would seem to be back on the table, throwing both Brexit’s and the prime minister’s future into doubt—if, that is, the opposition can finally rouse itself to action.

Even in these less-than-normal times, one would expect such high-stakes, eleventh-hour games to produce a change in government. Perhaps more than that, one would have expected the two no-confidence votes, the three rejections of the prime minister’s Brexit deal, the twenty-two ministerial resignations, and the humiliation of a 26 percent approval rating to have ousted Theresa May and the Tories out of power long before this latest turn. But even as the prime minister has lost the support of her party, her Parliament, and her people, her political fortunes have remained buoyed by the misfortunes of a divided and desultory opposition.

For the past two and a half years, the Labour Party has been conspicuously absent from the political crisis that has been described as the nation’s greatest since the Second World War. Part of the reason for that is simply structural, a consequence of Britain’s majoritarian Parliament. Without a division between the legislative and executive branches, without a second elected chamber, and without a filibuster, there is little in place to empower political minorities who have not been included in the governing party’s coalition. In theory, this can release much of the gridlock that builds up in a more bipartisan system like the Untied States’. In practice, however, it simply tosses one set of partisans to the side.

A bigger factor, though, has been the Labour Party’s general disarray. While much attention has been paid to the Conservative Party, its divisions, and its messy mismanagement of the Brexit process, the reality is that Labour has not been much better. “Labour’s divisions are comparable to the Conservatives’,” Thomas Raines, head of Chatham House’s Europe program, told me. In fact, the divisions are nearly a mirror image: Where 39 percent of Conservative voters voted to remain and 61 percent voted to leave, 65 percent of Labour voters voted to remain and 35 percent voted to leave—burdening both parties with fractured constituencies and fragile mandates. And just as a Remainer, Theresa May, was uncomfortably put in charge of the more pro-Brexit Conservatives, a Leaver, Jeremy Corbyn, was left in charge of the generally anti-Brexit Labour. The new political identities have not sat well with either party, leading both sides to be split, perhaps irrevocably so, and giving Corbyn good reason to keep his party’s fight from coming to the fore.