The parties’ manifestos tell a new tale of political division. The deep gulf in national opinion revealed by the Brexit referendum is reflected across the main parties; each is struggling to adjust to the uncomfortable discovery that its voters are not thinking what it thought they were thinking. The Tories and Labour are in the process of transformation. The Liberal Democrats, in startling contrast, are – metaphorically speaking – lashed tightly to the mast, committed to the course they embarked on long before the weather turned.

That explains why the top line of the party’s manifesto that is to be formally launched on Wednesday night is the promise of a second referendum on whatever deal finally emerges from the Brexit negotiations. It is completely in line with the party’s bold decision last year to pitch itself as the voice of the 48%. But it’s beginning to look like rubbish politics, and there are plenty of senior Lib Dems who said so all along. Step forward, Vince Cable. But the EU has been at the core of the party’s being since it took shape in the wake of the first Euro vote; anything else must have risked appearing a betrayal of fundamental principle. It seemed, too, to point to a way out of the 2015 catastrophe. It offered a new and positive identity that would at least soften the memory of the coalition years; and it seemed crowned with success when the party snatched Richmond from the Tories in a byelection at the end of last November.

The trouble is that the remain vote has turned out to be much flakier than it felt last June, or even at the time of the Richmond byelection. Polling now suggests that as many as half of those who wanted to stay in the EU are ready to knuckle down and get on with leaving. The wound is healing.

Unsurprisingly, this is not turning out well for the party. Instead of the usual election pattern of the Lib Dems picking up support as their name recognition and familiarity grows, this time it seems to be leaking away. Outside London and the south-east of England, campaigners are barely fighting on the national platform at all. They are fighting old-fashioned local campaigns about schools and hospitals. It’s almost like the old days of Liberal Focus newsletters highlighting the party record on bin collection and pavement repairs.

Fortunately there is a common factor that links activists and leadership: on the doorstep and in the TV studios the party is arguing that its objective in this election is to be the real opposition. Obviously, this pitch is partly forced on it by the overwhelming lead the Tories have in the polls and the complete implausibility (although not one that used to trouble them) of setting out a programme for government. All the same, it makes this year’s manifesto even more of a branding exercise than they normally are.

What is clear is that the party has not completely chucked out Orange Book liberalism: for example, it remains committed to balancing the budget by 2020, which is more than even George Osborne would do, and much more than Theresa May. An extra £6bn a year for the NHS and social care would be paid for by putting 1p on the basic rate of income tax. The nastiest of the latest cuts to welfare (remembering that, however reluctantly, the party conceded many others) – the no third child, housing benefit and all working age benefits – will be uprated at least in line with inflation. There is a big commitment to housebuilding. There are the traditional pledges on devolution and welcome support for a constitutional convention to examine the governance of the United Kingdom. There is even that eyecatching commitment to legalise cannabis.

In his manifesto launch speech, Tim Farron tries to bridge the chasm between devoted remainers and determined Brexiters; he insists that he respects the referendum result. But there are few concessions to the other half of the country. On immigration, the manifesto suggests some form of managed system of work permits and visas, but there will be no target. The Lib Dem rejection of a hard Brexit creates the familiar dilemma between having both the single market and free movement, or neither.

To some degree, all parties always mean different things to different voters. But the referendum has left a livid scar through the country’s politics. Lib Dems in the south-west or in Norfolk, say, who once ignored some of their party’s more fashionable policies because for them it was the natural party of opposition, are newly sensitised to what voting Lib Dem means, and too often that means only opposition to Brexit. Farron and his manifesto are a defence of the essence of liberal Britain: open, tolerant and outward-looking. Fabulous, but not necessarily in a good way.