Brexit may yet kill the Conservative party but it is exacting a cruel psychological torture on liberalism. Liberals are supposed to be the measured voice of reason – earnest, insufferable but reliably level-headed. Not anymore.

Liberals – or at least some of them – have gone quite mad over Brexit. There is almost no intrigue they will not seize on if it might explain away the last three years.

TV historian Dan Snow tweeted a photograph of his postal ballot and the Brexit Party leaflet he claimed had been delivered inside the same envelope. When celebrity Twitter flicks on its blue-tick sirens, craven officialdom comes running but they brought bad news.

Snow’s local council released a statement saying postal votes were handled internally and double-checked; it was ‘very unlikely’ that Brexit Party literature could have arrived in the same envelope. ‘Rather,’ they said with no little diplomacy of phrasing, ‘it is likely that the leaflet was delivered on or around the same day as the postal voting pack, which is how this misunderstanding may have arisen’.

Snow’s initial tweet racked up 3,500 retweets; his follow-up, admitting ‘a prank or incompetence on my part’ was likely to blame, managed a mere 300.

Snow’s flakery is far from isolated. Brexit angst is driving liberals to take positions they would have recognised as reactionary and illogical not so long ago. Decrying the BBC has become de rigueur in a way once confined to Tory conference fringes and mad academic symposiums on Zionist control of the media. Some remainers have convinced themselves the Corporation is pushing not only a pro-Leave agenda, but a pro-Farage one; some now openly question Auntie’s future.

Most of these charges focus on particular presenters, interviews or formats the accuser disapproves of. More worrying are those who question the virtue of due impartiality itself, simpering babyishly that broadcasters should instead air ‘The Truth’. Happily enough, The Truth just happens to match their own worldview, perhaps with an occasional nod to benighted opponents and their wrongthink.

Liberals on this side of the Atlantic have become as accustomed as their analogues on the other side to blaming their defeats on nefarious Russian plots. That’s not to say that the Kremlin doesn’t seek to influence elections in the West (it does) or that Putin wouldn’t favour the destabilisation of a rival superstate (he would). But liberals have fashioned a soothing parable in which a few Russian troll farms are all that’s stopping the people of Sunderland from embracing their inner European integrationist.

Those who weren’t brainwashed by Boris the Bot were motivated by ethnic prejudice. A fair whack of Remainers are positive their opponents are knuckle-dragging bigots. This view seems particularly prevalent amongst Labour members, though I suppose when it comes to racism they should know.

Tell yourself often enough that your opponents are Freddy Krueger and you will come to resent all democratic niceties and wonder if a more direct approach might be in order. Accosting politicians (the good ones) and shouting at them is A Threat to the Fabric of Our Democracy; accosting others (the bad ones) and hitting them with a milkshake is not. As a result, nominally-liberal commentators are dunking their own reputations to excuse what the police treat as common assault.

One of the reasons Brexit has been so traumatic to the liberal psyche is that the masses listened to the grave warnings of the gatekeepers then proceeded to blow the gates off their hinges anyway. The principle of no platform for fascists came into its own on the campus in the 1970s.

But since then deplatforming has gone from situational tool to central credo of the progressive worldview. Narrowing the scope of democratic debate has become one of the objects of modern liberalism.

This has been troubling to watch for those of us who are liberals, not least because the ideology of deplatforming has moved beyond skinheads to target anti-immigrationists, gay marriage opponents, Zionists, gender-critical feminists and Brexiteers. In the woke future, everyone will be fascist for 15 minutes.

Brexit upended this arrangement by forcing into the democratic realm a matter that had been carefully restricted to political, bureaucratic and foreign policy elites for 40 years. Liberals can’t police the boundaries of the debate anymore and, what’s worse, are actually having to have a debate.

This is unfamiliar territory and many diehard Remainers don’t make a case for the EU but a case against the people who are against it. They are anti-anti-Europeans bewildered by their estrangement from the reassuring political certainties shoved aside by Brexit. As they stumble around, bellowing one minute and weeping the next, liberals are every middle-aged man who isn’t handling the divorce well. She’s turned the C2s, Ds and Es against us.

Liberalism remains the most freedom-expanding, utility-enhancing, democracy-enshrining philosophy on the go. The European Union is still the greatest guarantor of peace, prosperity and security this side of the United States. Yet the foes of these ideas and institutions — populist, nationalist and authoritarian — are advancing and being met with hypocrisy and hysteria. Liberalism is having a nervous breakdown at the very moment we need it most.