How seriously should one take the Labour manifesto? In a serious election it ought to matter a lot. Yet everything about Labour at the moment – the manifesto included – reflects the sleepless battle for control of the party, rather than any serious engagement with non-Labour Britain. Oddly, though, this means there is some unity about the manifesto. The Corbynites want to run on a leftwing manifesto for reasons of ideology, but Jeremy Corbyn’s opponents want that too, so that Corbyn can own the defeat they expect on 8 June.

The much larger questions, especially to the three-quarters of British voters who are not Labour supporters, are whether this is a plausible manifesto, and whether there is a large and sustained appetite for a government dedicated to rolling back the Thatcherite counter-revolution. Don’t rule that out. But a manifesto is also only as plausible as the leader who presents it. I’d be lying if I didn’t say I think most voters have made up their minds on that.

There will, though, be many whose hearts beat a little faster on hearing that Labour would bring public ownership back into the railways, the energy suppliers and the Royal Mail, whose spirits rose at the prospect of tax rises for the 5% of highest earners, with reversal of inheritance and corporation tax cuts, who were cheered by big spending pledges on the NHS, social care, schools and student finance, and who were bucked by pledges on rights at work and a lower retirement age.

Too often Labour offers an attitude and a piety rather than an analysis: scrap this, ban that, reverse the other

Only those on the centre-left whose hearts and brains have calcified irrevocably against every traditional marker of a government for the common good could fail to respond to at least some of these possibilities. Modern disparities in wealth, reward and opportunity are shocking and should be righted. Many of the manifesto’s others ideas, even when it gets the answers wrong, ought to be much more central to political debate than they are.

But the wish that things should not be the way they are is not a good enough reason to embrace the manifesto as a whole. The crucial questions are not whether its aims are desirable – some of them are, others aren’t. The real questions are whether these aims are attainable, effective, affordable and politically sustainable and, above all, whether they are the most pressing priorities in such a fundamentally changed and changing country as 21st century Britain.

That’s where doubts must be taken seriously, not brushed aside. In the sections on energy and rail, there has been a bit of new thinking about the role of the state, including the local state (it would help if there was a local state in England). And it is worth stressing that wholesale nationalisation is not actually being offered here. This is a more nuanced prospectus than the rightwing press is pretending. But the manifesto is starry-eyed about the role of the state in the economy. It’s as though 20th century Britain never got anything wrong. There is an unmissable sense of turning the clock back.

Facebook Twitter Pinterest Senior Labour politicians. ‘Many of the manifesto’s others ideas, even when it gets the answers wrong, ought to be much more central to political debate than they are.’ Photograph: Paul Ellis/AFP/Getty Images

What, though, is the point of renationalising Royal Mail except to deliver to trade union vested interests, for example? Or of putting the health minister in charge of what would become a fearsomely centralised NHS? And what is the national good or the new thinking in several of the other goodies in the package for Britain’s too often unreconstructed unions? Sectoral collective bargaining is 1970s union power revisited, not a more modern focus on co-determination. Union power is not the same as workers’ rights.

Too often in the package, Labour offers an attitude and a piety rather than an analysis or a look forward: scrap this, ban that, reverse the other. It would be cheap to dismiss the manifesto as merely a Labour wishlist, but the leak doesn’t contain enough honest thinking about practicalities either.

Citizen co-payment for public services is a major case in point. Should Labour really abolish tuition fees for the middle classes, many of whose children have gone to private schools, others of whom can well afford them? Does Labour care if the elite universities decide to go private and make themselves a British Ivy League for rich kids from around the world? The main problem in the NHS is not creeping privatisation or charging. The problem is rising treatment expectations of a growing and ageing population, and rising costs. Throwing billions more at the NHS is popular, but it’s the easy bit. No organisation that employs 1.3 million staff should get a free pass in this way.

Labour's draft manifesto: key policies analysed Read more

Then there are the fudges and omissions. Three of them matter a great deal. The first is Brexit, on which Labour’s support for Europe (though perhaps not Corbyn’s) is pegged back by its fear of its lost working-class leave voters. The second is immigration, where a similar paralysis has resulted in a meaningless section. And the third is Trident, where support for renewal is undermined – at least in the leaked draft – by some waffle about caution and a slippery pledge to review it all in government. Given the saliency of all three issues in the media and in the Conservative campaign, Labour could be heading into the election decked in cardboard armour.

Yet the draft manifesto is not, as was said of its 1983 predecessor, a suicide note. In many ways the 1983 manifesto it most resembles is that of the Liberal/SDP alliance, though the Labour draft isn’t quite as progressive as the alliance’s. If Labour dies on or after 8 June – which, for all its problems, I doubt will happen – it will be from a long series of self-inflicted wounds, including some very terrible ones inflicted by Corbyn, and a failure to treat them.

It is wrong to pretend this is a scary manifesto, though that won’t stop the Daily Mail. The real criticism is that it’s an iceberg that is all tip and no berg. It contains some good things and some bad, some interesting ideas and some lazy ones. There are things that will resonate with Theresa May’s red Tory advisers, and more widely. What it is lacks, though, is a sustained hinterland of soundly constructed credibility.

The leaking is a reminder, to those who pay attention, that this is a dysfunctional party. Labour’s real problem is that not enough people are paying attention any longer. It will take more than a manifesto to change that.