Last September, Andrew Marr, the host of a Sunday morning political show on the BBC, interviewed Theresa May, the Conservative Party politician who had succeeded David Cameron as Britain's Prime Minister after the Leave side’s narrow victory in the Brexit referendum, in June. With the Conservatives holding a big lead in opinion polls over the opposition Labour Party, Marr asked May whether she was tempted to call a snap general election, which could conceivably have enlarged her government's narrow majority in the House of Commons.

“I don't think there is a need for an election,” May replied. “I think the next election should be in 2020.” Marr pressed May again, asking if her answer was absolutely certain. “I am not going to be calling a snap election,” she said. “I’ve been very clear that we need that period of time, that stability, to be able to deal with the issues the country is facing—and have that election in 2020.”

On Tuesday, May announced that Britain would go to the polls on June 8th, which is just seven weeks away. Citing continuing divisions in Parliament regarding the Brexit process, she said, outside of 10 Downing Street, “I have concluded that the only way to guarantee certainty and stability for the years ahead is to hold this election and seek your support for the decisions I must take.”

This explanation didn’t withstand inspection. Although Britain as a whole remains bitterly divided by Brexit, May faces little effective opposition at Westminster. Earlier this year, the House of Commons voted overwhelmingly to allow her to start the formal process of breaking with Europe, which she did last month. And although May's government has run into a bit more trouble in the House of Lords, it has dealt with that reasonably effectively, too.

The real reason behind May's gambit is that the Labour Party is currently so weak that she seems all but certain to win on June 8th and further strengthen her position. Opinion polls show the Conservatives leading Labour by more than twenty points. Writing in the Guardian on Tuesday, the conservative columnist Matthew d’Ancona noted that calling a snap election was “self-evidently the smart option.” A victory for May and the Conservatives, he wrote, “would kill off the idea of a second referendum, and close down the argument that the electorate had not given consent to withdrawal from the single market.” The Economist_ _pointed out that May “also has in mind her lack of a direct mandate: she has never won a general election, having succeeded Mr. Cameron as prime minister only via a Tory party leadership contest.”

So much for May, who has already proved herself to be an adept, slippery politician. What about Labour and the other opposition parties, including the Liberal Democrats and the Scottish Nationalists? Surely, they should be able to exploit the Prime Minister's brazen U-turn and her declaration that she wouldn't take part in head-to-head television debates during the election campaign. At least two attack lines suggested themselves immediately: “Flip-flopper!” and “Chicken!”

Unfortunately, for anybody hoping that it isn't too late to defeat the government and halt Brexit, things aren't so simple. May's decision to call an election only makes more clear that progressivism in the United Kingdom faces a crisis. In an ideal world, all the pro-European, internationalist, and progressive forces in the country would come together to transform the upcoming election into a second Brexit referendum—which conceivably could be won. But the opposition to May is so weak, divided, and compromised that this doesn't appear to be an option.

The main problem is the Labour Party. During last year's referendum, the Party's leader, Jeremy Corbyn, a veteran leftist, campaigned on the Remain side, although without much enthusiasm. (Some leftists still regard the E.U. as an inveterately conservative, pro-capitalist club.) Earlier this year, Corbyn flipped to the other side, ordering Labour M.P.s to support the bill giving May authority to trigger Article 50 of the European Treaty, which countries are obliged to invoke if they want to leave the E.U. It was only with Labour's support that May amassed such a large majority for the Brexit bill.

There was cold political reasoning behind Labour's adoption of this strategy. In the Brexit referendum, many traditional Labour voters went for Leave. Corbyn and some of his M.P.s feared that that if they didn't publicly accept the result, they would lose a lot of support, particularly to the anti-E.U. U.K. Independence Party, which has been gathering strength in working-class areas. Labour made a tactical decision to side with May, while reserving the right to reject the final exit agreement she reaches with other members of the E.U. Subsequently, the Party issued a list of tests it would apply to such a deal, which included things like retaining access to Europe's single market. Effectively, Labour is now committed to what’s known as “soft Brexit.”

While it might be easy to sympathize with Labour's predicament, the decision to compromise represented a triumph of short-term thinking over principle and Britain's long-term interests. Since the Party has recently voted for Brexit, it can hardly turn around now and base an election campaign on the argument for staying in Europe. In a statement on Tuesday, Corbyn welcomed the election. But, rather than focussing on Brexit, he said, “Labour will be offering the country an effective alternative to a government that has failed to rebuild the economy, delivered falling living standards and damaging cuts to our schools and N.H.S.”

Important issues all; but this was the statement of a politician who has been cornered on the issue that will define Britain’s future. Theoretically, Labour could still replace Corbyn before the election and switch to an anti-Brexit platform, but that seems extremely unlikely. Although he is unpopular among Labour M.P.s and scores horribly in opinion polls, Corbyn retains a lot of support among the Party’s grassroots membership, which picks the leader.

With Corbyn and his platform seemingly locked in place, the only major parties offering an explicitly anti-Brexit alternative are the Liberal Democrats and, to a lesser extent, the Scottish National Party. “This election is your chance to change the direction of our country,” Tim Farron, the leader of the Liberal Democrats, said on Monday. “If you want to avoid a disastrous hard Brexit, if you want to keep Britain in the single market, if you want a Britain that is open, tolerant and united, this is your chance.” Nicola Sturgeon, the head of the S.N.P., described the decision to hold an election as “a huge political miscalculation.”

The fact is, though, that neither the Liberal Democrats nor the S.N.P. is in a position to form a new government. Having been decimated in the last general election, which took place in 2015, the Lib Dems have only nine seats in the House of Commons. The S.N.P. has fifty-four, all in Scotland. To obtain a majority, a party needs to win three hundred and twenty-six seats. The Conservatives currently have three hundred and thirty, along with some support from smaller parties.

In other political systems, the obvious solution would be for the progressive, internationalist parties—in this case, Labour, the Lib Dems, and the S.N.P.—to form an electoral alliance, formal or informal, against the nationalist conservatives. Given the gravity of the situation, and the narrowness of the result in the Brexit referendum, there are strong, perhaps overwhelming, arguments for this to happen. At this juncture, however, it looks like a fantasy.