Whether you call it a schism or merely a split , bitterly divided parties are nothing new when the stakes are highest for the country…

English Reformation, 1534

Brexit means taking Britain’s signature off the treaty of Rome, a cue for comparisons with Henry VIII’s repudiation of the jurisdiction of the pope. The Tudor king had several motivations, not least the need to find a wife who would produce a male heir. A major consequence of this was to separate Britain from much of the continent by giving it a different state-approved religion from most other European states.

As with Brexit, the Reformation unleashed bitter struggles about sovereignty, identity and authority under Henry and several of his successors. As with Brexit, it divided families, turned friends into enemies, generated fabulously arcane doctrinal disputes and martyrs of both faiths. Many members of the governing class ended up on the scaffold. Mercifully, no one has yet suggested Brexit arguments be settled by burnings at the stake, but the deadly ferocity of the struggle between Catholic and Protestant finds an alarming echo in the violence of the language used by some Brexit protagonists.

Imperial preference, 1902-1937

Witnesses of the Tory party’s unity-shredding convulsions over Brexit often look for similarities with the Conservative split over the Corn Laws under Sir Robert Peel in the first half of the 19th century. A less-cited, but perhaps more useful, comparison is with the Tory party’s battles with itself over “imperial preference” in the first half of the 20th century. A group led by serial party splitter Joseph Chamberlain, egged on by right-wing press barons, wanted to renounce free trade and replace it with preferential tariffs for the colonies and dominions of the empire. Their claim was that this form of protectionism was a patriotic policy, and would sustain Britain’s global power against its rivals.

There’s a connection with those Brexiters who radiate nostalgia for empire and a yearning to somehow recover lost international clout. Divisions over imperial preference contributed to the Tory party’s defeats in the elections of 1906, 1923 and 1929 – examples of the often reliable rule that divided parties lose votes.

Cold war, 1945-89

Some suggest Brexit will be one of those struggles that will be fought out over a generation or longer. Similar, then, to the cold war, which defined people and politics over decades because it asked fundamental questions about who they were and where they stood. Like Brexit, the cold war was a splitter of political parties. In this case, most of the splitting was done by Labour, which repeatedly warred with itself about whether it should support or reject the possession of nuclear weapons as a deterrent to the Soviet Union. Battles over the bomb were especially fierce during Labour’s long period of opposition after 1979.

They also proved irrelevant. By the time Labour returned to power in 1997, the cold war was over. There is a lesson in there somewhere. Very much against general expectation, the cold war ended not with a bang, but with the largely peaceful dissolution of the Soviet Union and its totalitarian bloc. Could there be a positive finale to Brexit? That would be another welcome surprise.