For most progressive-minded, remain-leaning folk, is it even a dilemma? I’m not sure. To them the logic must seem simple and straightforward: they want to eject a cruel and useless government and stop Brexit, and that means denying Boris Johnson a majority and replacing him with Jeremy Corbyn, who will end austerity and hold a second referendum. Job done.

I wish it were as simple as that for me. But it’s not.

For more than four years, Britain’s Jews have waited for the moment when one of these revelations would prove too much

Because while I want desperately to avoid Brexit, and while I have nothing but contempt for Johnson and his hard-right party, the prospect of Prime Minister Corbyn fills me with dread. Not, I stress, the prospect of a Labour government, committed to spending billions on schools, hospitals and houses – Britain needs that badly – but specifically the notion of Corbyn and his inner circle running the country. The thought of it prompts in me, and the overwhelming majority of the community I grew up in, a fear that we have not known before.

I’m referring to Britain’s Jews who, for the first time in their history, have concluded that someone hostile to them is on the brink of taking democratic power. Yes, of course, not every single British Jew holds that view. But the most recent poll found that 87% regard Corbyn as an antisemite, meaning an anti-Jewish racist.

Why? The recitation is now wearily familiar. Recall that Corbyn’s first reaction on hearing of a plan to remove a mural filled with hideous caricatures of hook-nosed Jewish bankers was to ask, “Why?” Or that he decided to challenge two “Zionists” not on their arguments but by suggesting that, though they “might have lived in this country for a very long time”, they “don’t understand English irony”. Or that, when a Palestinian Islamist preacher was found by a British tribunal to have peddled the medieval and lethal myth of Jews feasting on the blood of gentile children, Corbyn declared that man a very “honoured citizen”, and invited him for tea in the House of Commons. (And those are merely some of the greatest hits; the full discography runs much longer.)

For four years, Britain’s Jews have – naively, perhaps – waited for the moment when one of these revelations would prove too much for the Labour faithful, shocking them into action. Perhaps it would be the discovery that, despite evidence against hundreds of party members – including those trafficking in grotesque neo-Nazi imagery and Holocaust denial – only a handful have actually been expelled. Or maybe it would be the BBC Panorama investigation that showed how Corbyn’s team repeatedly interfered in antisemitism cases as they went through a supposedly independent disciplinary process, “mainly so they could let their mates off the charge”, as one whistleblower, driven to the brink of suicide, put it. Or perhaps it would be the fact that Labour has become only the second political party ever to be investigated for institutional racism by the Equalities and Human Rights Commission (the other was the BNP).

But no. No revelation has ever proved shocking enough that it couldn’t be explained away by those who’d rather not see it. So publicly Labour’s luminaries insist they are fighting a “ruthless” fight against antisemitism, doing all the Jewish community has asked of them, as John McDonnell said this week, even though the facts point the other way.

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We’re meant to cheer that Chris Williamson has been barred from standing again as an MP. But Jews remember that, even when Williamson’s penchant for egregious Jew-baiting was well known, Corbyn was still praising him. Just a few months ago, in fact, Corbyn called him “a very good, very effective Labour MP. He’s a very strong anti-racist campaigner. He is not antisemitic in any way.”

None of this has stopped. Labour’s crop of prospective parliamentary candidates has included several with a documented history of anti-Jewish bigotry, Twitter back-catalogues playing on all the familiar tunes of Jewish conspiracy, greed and the rest of it. Two candidates were forced to step down on Thursday, one for calling a Jewish fellow councillor “Shylock”. It suggests this is no longer a problem of one man, but that the malaise is now institutional.

And yet Labour’s high command could soon be governing the country. Labour doesn’t even need to win many seats; Johnson needs only to fail to win a majority and Corbyn will be closing in on Downing Street. What should Jewish voters and those appalled by anti-Jewish racism do about that?

Plenty advise Jews to shelve their angst in return for a government that will stop Brexit (Jews are overwhelmingly pro-remain). In effect, Jews and their would-be allies are being told that some racism is, if not quite acceptable, then a price worth paying. That seems to have been the bargain struck with those Labour “moderates” who were once so admirably vocal in their denunciation of the leadership on this issue and who are now – minus Tom Watson – knocking on doors to put Corbyn in No 10: you’ve got your second referendum, now shut up about the Jews. It’s an uncomfortable feeling, to be part of a small community that can be so quickly cast aside for the supposed greater good.

Progressives and remainers who care about racism are left with a dilemma. Some try to swerve around it by denying the evidence, telling Jews they are wrong about the racism they experience. That’s not a great look. Others (rightly) point out that Johnson is himself a bigot and an Islamophobe – as if we should accept that this is a contest of two racists and we should back the one we agree with more. Still others war-game assorted hung-parliament scenarios that might magically both despatch Johnson and deliver a non-Corbyn prime minister.

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But all of this is to dodge the main point – which is that none of us should have ever been put in this position. None of us should be forced to choose between a hard Brexit enforced by an Islamophobe, and electing a man whose record fills one of Britain’s smallest minorities with fear.

Many, Jews included, ask themselves how bad would it really be. What’s the worst that could happen? Of course this isn’t the 1930s and, despite the Sunday Telegraph’s front page, most Jews would not leave the country. But that the question is even in the air, that someone who sees Jews as not quite “us” – “they don’t understand English irony” – is deemed eligible to be prime minister, makes our presence here feel conditional and shaky. And, whether Corbyn makes it to Downing Street or not, to realise that the historic party of social justice in this country finds a little bit of racism acceptable for the sake of the larger cause, and that many millions of voters agree – well, that realisation contains its own heartbreak. It means that what we thought about this country wasn’t quite true.

I understand that to many, all this will sound overwrought. I’m afraid that Jewish history has made us that way, prone to imagining the worst. We look at our usually sparse family trees and we can pick out the pessimists, those who panicked and got out. It was they who left their mark on us. You see, the optimists, those who assumed things would work out for the best, they never made it out in time.

• Jonathan Freedland is a Guardian columnist