Political historians like to talk about ‘watershed’ elections—elections that, either immediately or in retrospect, act as milestones for a paradigm shift within the electorate and a tangible sea change in wider society. The UK is more than familiar with such moments. For students of politics, years like 1931, 1945, 1979, and 1997 are etched so indelibly in their consciousnesses that the mere mention of these numbers is enough to conjure up visions of entire epochs of British history. For Europe, 2019 has a strong claim to be just such a watershed moment. In the European Parliament that is emerging from the 28 May elections, the long-lasting duopoly of social-democratic and Christian-democratic party groups has all but ended, declining from 412 out of 751 MEPs in 2014 to 332—losing their EP majority. This has been matched by a significant boost to parties in the liberal/green centre-left and national-populist far-right groups, up from 165 to 286 MEPs in total.

The UK too was far from immune to these forces, despite its almost accidental participation in the elections. Much of the fixation in the subsequent analysis was on the impressive performances of the Brexit party (30.5% of the vote; 29 MEPs) and the Liberal Democrats (19.6%; 16 MEPs), and the UK-specific ‘Remain/Leave’ dimensions of the vote. But viewed in terms of ideological groupings, 2019 in the UK was also a significant defeat for the ‘traditional’ parties of left and right, who scored a mere 22.4% and 14 MEPs in total. And it saw a surge for the centre-left as well—Liberal Democrats, the SNP, Plaid Cymru, the Greens, Alliance, the SDLP, and Change UK took 41.1% and 28 MEPs in all—and the national-populist right, who garnered 33.8% and 29 MEPs for the Brexit party and UKIP combined. Ironically, in other words, a result entirely in line with European trends.

If the local elections had left anyone in any doubt, the European elections have made resoundingly clear that Labour urgently needs to change its Brexit stance. But more specifically, the precise results of 28 May (or technically 25 May for the UK) have strengthened to the point of being unarguable the case for Labour to soften this stance, not harden it.

There are three reasons for this. First, the surface-level dynamics of who won and who lost. Remain won a plurality of votes. Hard (i.e., No Deal) Brexit did not. Even if the Conservatives are read as hard Brexit too—as seems justified given the trajectory of their upcoming leadership election—Brexit is still only capped around 41.6%. The question is: where does the Labour vote belong? If Labour is included with the Remain total due to the 70% of its membership who still favour staying in the EU, Remain won a majority: 54.8%. If Labour is instead counted as soft Brexit due to its leadership’s position, then—and only then— did Brexit in some nebulous form won a majority: 55.3%. Arguably, the 34% cap (or, more generously, 42%) for hard Brexit is a fairly durable ceiling. As a European election, fought explicitly on the issue of EU membership—despite the Labour leadership’s frankly bizarre attempt to tack to ‘local issues’ in the campaign—there was no reason for anyone who desires hard Brexit to vote tactically in this election, rather than in line with their principles.

Second, the internal dynamics of who stayed with Labour and who switched elsewhere. Post-election polling carried out by Lord Ashcroft found that, of voters who had cast their ballots for Labour in the 2017 General Election, only 38% stayed with Labour in 2019, with 22% switching to the Liberal Democrats, 17% to the Greens, and a mere 13% to the Brexit party. (The remaining 10% scattered among the smaller parties, with the largest contingent switching to Change UK.) In other words, Labour’s Brexit position cost it well over half its voters, and of those, it lost around three times as many to the centre-left as to the national-populist right. Out of Remain and hard Brexit, it seems it is the former that holds far more promise as an avenue for Labour to bolster its electoral appeal.

Third, the expected parliamentary dynamics in a future General Election. Unlike previous European elections, where the heights of electoral support reached by ‘third parties’ (UKIP, but also more recently the Greens) failed to translate into success at Westminster, the voteshares from May 2019 are so far proving somewhat more durable in the Brexit-dominated context of current Westminster politics. The most recent YouGov, Opinium, and Deltapoll figures have even seen the Brexit party (22-26% range) and Liberal Democrats (16-24% range) partly or entirely supplant Labour (19-26% range) and the Conservatives (17-20% range) as the two largest parties. Yet the vagaries of the first-past-the-post electoral system give the latter a prodigious advantage, and reliable models still show these figures leading to a hung parliament with Labour in the most favourable position (anywhere between 32 and 74 seats off holding a Commons majority). In such a scenario, Labour would be compelled to rely on ‘third parties’ to form any future coalition or ‘confidence and supply’ arrangement. Since the largest of them (SNP, Liberal Democrats) favour Remain, bringing about some kind of rapprochement with Remain lies in Labour’s interest in being able to form a future government that implements a left-leaning programme of domestic policies too.

This is the context in which Labour has committed to a second referendum, essentially caving under intense and sustained pressure from People’s Vote activists and Labour Remainers. But the party needs to be very careful. The logic of electoral legitimacy has not changed. If Labour merely supports a ‘rerun’ of 2016, Brexiteers will scream betrayal. In opinion polls on Remain versus Leave, the numbers do seem to have shifted, but only to a 50s versus 40s position (i.e., a reverse of the last referendum). And as critics of a second referendum have continually pointed out, there is no guarantee on those numbers that Remain would definitely win second time round.

So what, from Labour’s perspective, should its second referendum strategy look like? The starting point, hard as it may be to believe, is that the UK is still technically in the extension period that was originally granted to give Theresa May more time to win MPs round to her Withdrawal Agreement. As things stand, that is still the deal on the table—with the EU neither inclined nor in the legal position to renegotiate it. So the priority for a Labour party that is to soften its Brexit position—given that it has already repeatedly rejected the Withdrawal Agreement for being too hard—is to ensure that any Deal option on the ballot paper in a second referendum is at worst no harder, and ideally considerably softer, than the Withdrawal Agreement as it stands.

Its goal must be to work together with MPs from the Remain parties (Liberal Democrat, SNP, Plaid Cymru, and Green) to make it impossible for the new Conservative leader to pass the Agreement in its current form. It must collaborate with these parties to form a joint centre-left alternative to the increasingly extreme-right vision Conservatives are offering for the UK’s future relations with Europe—realistically, one that includes at minimum EFTA membership or a close equivalent. If—a big if—it resumes negotiations with the Conservatives, it must do so only as the representative of this collective position, and must stand its ground and refuse any compromise that does not accommodate this position’s concerns.

Above all, as a party of the left, Labour must do whatever it takes to block No Deal. The importance of this point cannot be overstated, because it is a cornerstone for  Labour’s credibility as a potential party of government. Labour’s concrete commitment to A Deal rather than No Deal, and to soft Brexit rather than hard Brexit—which are not only in its electoral-strategic interest but also, by any plausible analysis, in the material interest of its voters—must take precedence over every other consideration. In practice, this means it must oppose No Deal being an option in a second referendum. It will already have made good on its commitment to seeing the 2016 referendum result implemented by supporting the negotiation of a soft Brexit deal. After all, this was the form of Brexit that even the most swivel-eyed of current No Deal advocates  pitched to the British electorate at the time.

Instead, Labour must accede to the claims of the centre-left, and push for Remain as the other option on the ballot paper. It urgently needs to regain the confidence of its departed Remain-leaning supporters, and to be seen as a credible partner by centre-left Remain parties, both in formulating an alternative Brexit offer and in future matters of domestic politics when (if) Brexit is finally resolved. To do so, it must make a move—and be seen to move—back towards reopening the prospect of the UK remaining in the EU after all.

Labour does not yet have to decide what its steer in a second referendum would be—whether it would back soft Brexit, Remain, or give its supporters a free vote. The point is that it must frame this referendum in such a way that either outcome—Deal or Remain—will be favourable to its voters, and electorally viable for it as a party. The outcome of the European elections has erased the need for Labour to agonise over choosing either party or country ahead of the other. Both imperatives now point in the same direction: guaranteeing the UK’s close future economic integration with Europe, whichever path voters choose to take.

Marius S. Ostrowski is Examination Fellow in Politics at All Souls College, University of Oxford. He is a social theorist and historian of twentieth-century political thought, and has written on European politics, ideology, public opinion, and the history of socialism.