IT WAS dubbed the “Easterhouse epiphany”. In 2002 Iain Duncan Smith was shown around that Glasgow housing estate. The then Conservative Party leader wept at the hopelessness he encountered on its litter-strewn streets and returned to London determined to do something for those who had lost out under Thatcherism. He was booted out of his job the following year, but pursued his vision (a socially conservative, globalisation-sceptic sort of Toryism) afterwards and in 2010 became work and pensions secretary under David Cameron. In a party striving to shake off its reputation for nastiness, his “Easterhouse modernisation” contrasted with the more metropolitan brand of renewal on offer: the “Soho” modernisation devised by well-heeled London Tories like Mr Cameron and George Osborne, now chancellor of the exchequer. This blended libertarian social policies with an interest in quality of life and environmentalism.

Since then the differences between the Easterhouse and Soho schools have sundered Mr Cameron’s government; never more so than on March 18th when Mr Duncan Smith resigned as work and pensions secretary. He blamed the government’s planned cuts to disability benefits: the culmination, he argued, of years of unreasonable demands by the Treasury. In truth his motives went deeper, concerning the EU referendum (he supports Brexit, unlike the party leadership) and even styles of working, thus exposing the tensions in a Conservative Party that spans multiple classes, age groups, social circles and ideological camps.

Indeed, this is just the latest chapter in the party’s long history of infighting. The Osborne-Duncan Smith split can even be compared to those over the protectionist Corn Laws in the 1840s (a wider argument which gave birth to this newspaper) or over European integration in the early 1990s. Which points to an awkward truth: were it not for Britain’s first-past-the-post electoral system, which rewards large, broad parties, the Conservatives would not sit together in Parliament at all. Under a proportional system, Mr Osborne might work with Blairites from Labour and free-market Lib Dems in a liberal party. Mr Cameron might join him, or lead his own Christian Democrat party. Mr Duncan Smith might club together with conservative Labourites like Andy Burnham. Other Tory MPs, like Priti Patel, might join figures from the anti-EU UK Independence Party in a new right-populist outfit.

Such divisions have always existed in Tory politics, but Mr Duncan Smith’s resignation—like the ongoing wars over the EU—crystallised them. Its aftermath saw his allies, like Ms Patel, clash with Mr Osborne’s, like Ros Altmann, a pensions minister who had worked under the welfare secretary. Word got out of Downing Street that Mr Cameron had called his predecessor-but-one a “shit” and blamed his ally, the chancellor of the exchequer, for making a mess of what had been supposed to be a boringly safe budget ahead of the EU referendum in June. The fray even generated glimpses of the leadership contest to come when the prime minister steps down: Boris Johnson, London’s mayor, using an appearance on a chat-show to declare Mr Osborne’s cuts unfair. Local Conservative associations are furious about the prime minister’s support for EU membership (and thus sympathetic to Mr Duncan Smith’s flounce) and there is dark muttering among MPs about a bid to oust Mr Cameron after the referendum.

So it remains possible that the Conservative Party will disintegrate over its culture wars. The next leadership election could exacerbate the splits, prompting Eurosceptics to peel away from pro-globalisation, Europhile colleagues. The associations may rise up against their own MPs. The Labour Party’s current hard-left torpor could give some Conservatives a dangerous sense of electoral immunity.

But therein lies the case for caution: the corollary of Tories bickering when the going is good is that (much more so than Labour) they generally pull together if up against it. When Mr Osborne went before Parliament to defend his budget on March 22nd, for example, an expected drubbing turned into a triumph as Conservative MPs bobbed up and down with friendly questions, cheering him when he answered. The same was true in the previous parliament: despite violent eruptions over proportional representation, House of Lords reform and gay marriage, the party knuckled down in the months before the election and helped the leadership win an unexpected majority at the polls.

It pays to disagree

In other words, the Conservative Party is a faithful product of first-past-the-post. It is a strikingly wide coalition spanning much of British society, but one with the will to power that is needed to subsume its differences in the cause of winning elections. Mr Cameron encapsulates this. He is rooted in his own tribe, the posh Berkshire set, which can make him blinkered and get him into trouble. But he succeeds by being studiously vague and obsessively competitive (advisers avow that he even takes pub quizzes much too seriously); when presented with bad polls last year he told aides to “physically attack me with the right words” to improve things. This mix of constructive ambiguity and energetic pragmatism is the route to victory in the British system.

Thus the Tories are still the party most likely to win the next election. When Mr Cameron goes they will probably pick a similarly mainstream replacement: Mr Osborne (down but not out following the recent dramas), Mr Johnson (who is only disingenuously Eurosceptic), Theresa May (the underestimated home secretary) or Stephen Crabb (Mr Duncan Smith’s dynamic replacement). Bridging such a wide part of the electorate will keep causing arguments, but it will also continue to give the Conservatives a greater reach than Labour; the reason they ran Britain alone for 47 years in the 20th century to Labour’s 22. In a country where people are growing farther apart, internal differences may prove as much an asset as a curse.

Economist.com/blogs/bagehot