Legend has it that a group of Liberal Democrats on the Isle of Wight once exercised their democratic right by putting the CND logo on their ballot papers rather than a cross. It was meant as a protest vote – though confusingly, one that was unrelated to nuclear disarmament. It is true that you don’t have to make your mark with a cross. In another episode involving Lib Dems, the party successfully argued that a voter who depicted male genitalia in their candidate’s box was nevertheless intending to cast a vote for them. That story has the benefit of being verifiable: the CND signs, unfortunately, not so much. I dredged though newspapers back to 1983, harassed academics, and dug into the annals of Isle of Wight politics, all to no avail.

If there had been a way to signal opposition to Brexit, the remain vote could have split any way and still been united

Why, you might ask, in the lead-up to elections that the far right is already visualising as a famous victory, did I fritter my energy away in such idle research? Utter frustration had a lot to do with it. Because imagine what the European elections would look like if you could signal – whichever party you voted for – that yours was a remain vote. Maybe it could be done through placing a star instead of a cross on the ballot paper. Or “a B with a cross through it”, as someone suggested to me, on the grounds that “nobody knows how to draw a star”.

This would have been game-changing for Labour voters, who could have supported the candidates they believed in without the threat of their vote being interpreted, post hoc, as a call to “get on with Brexit”. It could have galvanised the not insignificant body of Conservatives who are pragmatic remainers, and have thus been denounced as traitors by the suddenly dominant extremists within their party. If there had been a way to signal unambiguous opposition to Brexit, the remain vote could have split any which way and still have been united.

In the absence of that, what is to be done? A month ago I wrote that remainers had nothing to fear from voting Labour. Jeremy Corbyn and Labour’s MEPs belonged to the party of European Socialists, and were therefore already signed up to the most visionary, transformative and radical manifesto the EU had seen since the earliest ambitions of its founders. Fourteen of Labour’s MEPs were allied to the campaign group Love Socialism Hate Brexit, and committed to a confirmatory referendum. Richard Corbett, Julie Ward, Jude Kirton-Darling and Seb Dance have been among the most vocal, prescient and persuasive critics of this Brexit shambles since 2016. The selection of candidates, including Momentum’s Laura Parker and ex-head of Best for Britain, Eloise Todd, suggested to me that the party was going to swing full-remain for these elections, and stay there.

But I had reckoned without the power of the “Lexit” faction, stuck in a fantasy world where the archetypal leaver is a working-class Labour voter of the north whose unchangeable and righteous wrath is more important and “authentic” than that of any remainer, whatever their class. As a result of their influence, the party finds itself in the absurd position of leavers thinking it is pro-remain, while remainers think it is determined to facilitate leave. Corbyn’s pledge to ensure the party unites leavers and remainers has been fulfilled, but only in one regard: none of us believe he’s truly on our side.

Perhaps you’re wondering: “But what’s the dilemma?” I’m no tribal Labour loyalist. I’ve left the party and come back. I’ve voted Green while still being a member of Labour. I was in it and critical of it for most of my youth; out and critical of it for some of this century. One year I did knocking-up duty while fully intending to spoil my ballot. (“I’m here to make sure you’re going to get out and vote,” I’d begin, “but equally, it is fine if you just write ‘bollocks to it’.”)

This time is different: first, it runs counter to every democratic instinct to see candidates you admire and not vote for them. The Labour candidates are the kind of representatives I would like to see populate the coming era of politics. They are pluralistic, imaginative, radical, ambitious, patriotic. There are Greens I’d say the same about (Molly Scott-Cato, for instance), but to live in London and not vote for a slate I think should be at the heart of the party’s future seems absurd.

Second, these elections may be of symbolic significance for our national politics. But they are also of pressing, concrete importance for Europe’s future direction. The rise of the far right in the European parliament constitutes an urgent threat to everything that matters to Labour voters, from human and workplace rights to climate crisis. More than ever, that parliament needs a coherent left bloc. And with Brexiters continuing to sabotage every conceivable Brexit and support for remain climbing all the time, we do need to at least plan for the possibility that these MEPs are in for the long haul.

Third, someone needs to oppose Nigel Farage, and that will come much more convincingly from somebody with a track history of fighting racism – Clive Lewis, say – than it does from a clubbable Lib Dem. The days when the mainstream right and centre were morally capable of resisting untruth, corruption and racism on their own terms are over: only Labour can do this.

Fourth, the party is moving: on the Andrew Marr Show, Corbyn committed to a confirmatory vote. Sadiq Khan promised to campaign “day and night” for remain, come the final say referendum that he now thinks a certainty. The shadow Brexit secretary, Keir Starmer, along with others in Labour’s cabinet, will accept nothing less.

It is a crushing frustration that, when you vote for a party with a mixed message, your message itself becomes mixed. Voting Labour will be an act of faith, trusting it to resolve itself as the natural party of remain. But there are voices within the party who justify what is, essentially, a Tinkerbell manoeuvre: they’ll only prevail if you believe in them.

• Zoe Williams is a Guardian columnist