The Staggers 8 July 2016 Wake up to the political reality - Brexit's blade is splitting Labour in two Now we know what it feels like to experience what religious historians call a "schism". Getty Sign UpGet the New Statesman's Morning Call email. Sign-up The blade of the guillotine is swift through the air. For a few seconds after it has thudded into its target, the crowd is silent, shocked, dumbfounded. Did that really happen? Is this real? We are living within those few seconds after the cut. Now we know what it feels like to experience what political scientists call a "cleavage", or religious historians a "schism". These words have their origins in the realm of blades, metal, knives, swords, sharp edges. They describe what happens when the body politic is shorn in two.The dynamics behind such moments may have built up over decades, but they happen in an instant. And then the political reality snaps back. In May 1920, reality snapped into focus for the Liberal Party at their National Liberal Federation meeting in Leamington Spa. This was the meeting that finally tore the Liberals apart. They had already been deeply divided by the extension of the Tory-Liberal wartime coalition beyond 1918. Ministers loyal to the Lloyd George faction were heckled by Asquith partisans, and walked out in defiance. The guillotine fell, and the party was irrevocably split. At the next election the fractured Liberals were overtaken by Labour, and they never fully recovered. There is more than one way for a party to respond to events, but the origins of that schism were buried deep in history. The emergence of a social divide between owners of capital and their proletariat workforce led to the build-up of political pressure, first through trade unions, then through the nascent Labour Party, and finally through the extension of the franchise in 1918. But the Liberal Party, too, was born of a split. More than 70 years before that, the decades-long battle between landowners and merchants over whether to control the price of corn finally reached its finale. That conflict had its origins in the Industrial Revolution. But the decisive moment – the moment which finally brought the landowner-merchant conflict to the forefront of politics – came in 1846 in Parliament, when the Conservative Prime Minister Robert Peel defied the landowning interests in his party to swing behind repeal of the Corn Laws. This split the Tories in two, and led swiftly to the birth of the Liberal Party. The divide which has led us to Brexit is just as longstanding. Tony Blair once described it as "open vs closed"; others call it "global vs anti-global", or "internationalist vs nationalist". There are cultural aspects to it, which could be described as "liberal vs conservative"; and there are material aspects to it too: "university-educated vs non-university-educated", for instance. The origins are complex. But the effect is clear. Imagine a biro on a piece of paper, drawing the same line over and over again. Eventually, the paper tears – and that is what happened on 24th June. It takes a piece of political chicanery to make the final split (God knows we have had enough chicanery in the last two weeks). But once it is done, there is no undoing it. There is no going back to the old party system, structured around a social cleavage (left vs right) which is no longer prominent. The political parties realigned in the 1840s, and again in the 1920s. They will realign again now. Labour is the party most in line for some kind of split. The new social cleavage runs clean through it. On one side are "heartland" Labour-voting Brexiteers, left behind by globalisation. On the other are liberal metropolitans of both the left and the centre (not just Corbyn and Corbynistas, but much of the wider Labour membership and parliamentary party too). What happens to the other parties – particularly the Conservatives and UKIP – depends to some extent on how Labour responds to its predicament. But whatever Labour does, we will see liberal, metropolitan Tories finding it hard to stick with their party in the new political landscape, and UKIP hoovering up both parties' spoils. In times like this, politics matters a thousand times more than usual. For a brief period, it really makes a difference what parties say, who leads them, and perhaps above all who joins them. History is shaped in fits and starts. The guillotine has fallen, but we do not yet know the consequences. This is a democratic moment – it is up to all of us to help shape what happens next. Will Brett is Head of Campaigns at the Electoral Reform Society, and writes in a personal capacity. › Commons confidential: Leadsamoney's loons Subscribe For more great writing from our award-winning journalists subscribe for just £1 per month!