The Tories want to back a winner. But they don’t know how to win

Two primal impulses are driving the Tory leadership contest: the desperate hunt for an election winner, and morbid fear of an election. Any tension between them is meant to be resolved by a Brexit miracle: the new prime minister releases Britain from European bondage on 31 October, and a thankful nation flings itself into outstretched Conservative arms.

It is always a mistake to expect gratitude from electorates. Voters see political pledges as a contract, not a favour, and they quickly move on to new demands. Labour’s victory in 1945 is the benchmark. If Winston Churchill couldn’t bank a VE day dividend at the ballot box, there isn’t much prospect of Boris Johnson getting one for some rickety Brexit bodge job.

The political map was simpler for most of the 20th century. In the 1955 election Labour and the Tories between them shared 622 out of 630 seats – 99% coverage of the Commons benches. The equivalent tally now is 560 out of 650, and that score might flatter the big beasts. The 2017 general election result looked like a return to old-fashioned two-party politics against a prior trend of fragmentation. Subsequent polls, including recent council and European parliamentary ballots, suggest the decay of traditional allegiances has returned and accelerated.

Related: Tory leadership: Johnson, Hunt, Gove, Stewart, Javid through, as Raab eliminated – live news

Labour took Peterborough earlier this month with the lowest vote share ever recorded by a byelection winner. The Tories were barged aside by the Brexit party, which didn’t exist a few months previously. Its boast to plucky newcomer status is a bit overblown, since it neglects Nigel Farage’s hardy perennial appearance in pretty much every campaign since the turn of the century. But that suggests his party won’t evaporate when the sun rises on Britain’s first day outside the EU.

Farage’s mission is to hunt down betrayal of the true Brexit vision, and he will sniff it out in any compromise any government makes to manage an orderly withdrawal. A significant portion of Tory members and an implacable cadre of MPs share that bottomless appetite for anti-Brussels grievance, infused with paranoid millenarian nationalism. These are people who doubt even Michael Gove’s commitment to the leave cause. They are waiting for a Brexit rapture that no prime minister can deliver.

Such fanaticism drives moderate Tories to the Liberal Democrats who, along with the Greens, are capitalising on Labour’s Brexit incoherence. Plaid Cymru are doing the same in Wales. There is no sign of revival for Scottish Labour, bulldozed by the Scottish National party. Boris Johnson would sabotage what progress Ruth Davidson has made for the Tories in Scotland. Running Britain is a game of Commons arithmetic, and when numbers stack up as they do now, in multiple columns, it is trickier for the two main English parties to reach commanding heights.

It is an irony of Brexit that the ambition to detach Britain from Europe has made UK politics look more continental: a spectrum of parties, none of which can govern alone. But even a slender majority would produce unstable government because the parties themselves are dysfunctional families, always on the verge of irreparable estrangement. There are Tory MPs who find the prospect of being led by Johnson repugnant and Labour MPs who think Jeremy Corbyn is unfit to be prime minister. Those dissenters might also be ambitious cowards who would stick around for the ride if their reviled leader wound up in power, but they would not be easy passengers.In such conditions, an essential quality of leadership is the capacity to build coalitions, between parties and within them. It is a clear lesson of May’s time in office that many Tory MPs ignore. They think her deficiency was in the performance side of politics and, having misdiagnosed the ailment, are ready to prescribe the wrong medicine. May’s most profound failing was in diplomacy and empathy. She could not cultivate relationships or nurture alliances and mostly refused to try. That narrowed her negotiating bandwidth in Brussels, and made it impossible to sell the deal she got back home. She could not even square it with the Democratic Unionist party, on whose support she spent buckets of public money.

Johnson is certainly clubbable, but even his club mates think he is an untrustworthy narcissist. Rory Stewart is the candidate offering some remedy to May’s shrivelled parochialism, simply by recognising that Brexit means accommodating interests beyond the tribal boundary of Conservative activism. In today’s cultural taxonomy, Stewart is Tory to his fingertips – fiscally disciplined, Eurosceptic, Etonian to boot. But he has confessed to Labour party membership in his youth (and tendencies that way in adulthood). His ecumenical style has engaged the imagination of at least 37 of his colleagues – the number that kept him in the contest in a second round of voting tonight – and some non-Tory audiences. It will still struggle to overcome the sectarian mood in the wider party.

The Tories are not ready for bridge-building, so they imbue Johnson with powers to arrange an electoral coalition by pure charisma. His magnetism must somehow lure both irate nationalists and despairing liberals. There was a time when Corbyn was similarly vaunted by his supporters as a man with a unique, gravity-defying capacity for political evangelism. That claim is heard less often now. The Labour leader talks about healing the nation’s European schism, yet his technique for doing it is obscure. He is polite to dissenters but closed to the opinions of anyone whose left trajectory has ever deviated from his own.

The Corbynite strategy looks more like a waiting game, being prepared to take a polling hit from disappointed remainers if the damage done to the other side by Brexit infighting is more savage. Underlying that calculation is a view that voters on the liberal-left, who protest in mid-term ballots, come “home” to Labour in general elections in order to thwart the hated Tories. Conservatives are thinking along similar lines. When their traditional supporters contemplate Corbyn in Downing Street they are supposed to quit dallying with Farage and come “home”. What the leaders say or do to make that happen is unclear. Their magical personalities dissolve all contradictions.

It would certainly be normal to expect a recovery in Labour and Tory positions in a general election. The two-party system has been written off before. Majorities have been declared impossible on the eve of polls that produced them – most recently when David Cameron beat Ed Miliband in 2015. But that already feels like a long time ago. The idea of anyone going “home” to Labour or the Tories underestimates the extent to which remain and leave are now many voters’ cultural domiciles. Those identities cannot conveniently be carved up by the established red-blue duopoly, and that makes forming and sustaining a government a lot harder. The Tories are fixated on the idea that their new leader must be a winner, but in this shifting political landscape they have no idea what winning looks like any more.

• Rafael Behr is a Guardian columnist