What would you think of a political party that promised to: cut unemployment by one million over two years; increase public investment; borrow more to finance extra welfare benefits and NHS staffing; increase foreign aid; promote worker coops; and aim for "a major extension of profit sharing and worker share-ownership to give people a real stake where they work"?

It's pure Corbynism isn't it?

Well, no. All these were in the 1983 Liberal-SDP manifesto. Back then, they were centrist policies.

Not that this was unusual. In 1924 - the year of picture opposite - Liberals called not just for workers to get a share of profits but also for the compulsory purchase of land for housing development and came close to advocating a land value tax.

By contrast, today's centrists show no such enthusiasm for empowering workers. The LibDems had five years in government without expanding worker coops an inch. Change UK (remember them) were silent on them. And the Labour right are hardly deafening us with their calls for greater worker democracy.

I suspect there's a simple explanation for this. Centrism is intellectually parasitic, preferring triangulation to developing its own ideas. Its support for coops and profit-sharing was a way of splitting the difference between the right's belief in private ownership and the left's in more full-blooded public ownership, and a way of trying to pacify a militant labour force. With workers having been defeated in recent years, however, centrists see no need for such pacification. Indeed, they don't even need to use the language of "capital" and "labour" as they did in the 1920s. Instead, they've retreated into the comfort zone of acquiescence to capital - as demonstrated by the post-Westminster careers of Nick Clegg and the Cukkers.

This explains something else - centrists' lack of interest in economic policy, or indeed policy generally. It's clear what they don't want - the sort of Corbynite policies centrists advocated in the early 80s. But it's much less obvious what their positive agenda is. What, for example, are their answers to the problems of inequality, stagnant productivity and real wages, unaffordable housing and so on?

We heard this vacuousness from Peter Mandelson on the Today programme yesterday (2'19" in). Nick Robinson asked him what changes he'd like to see Labour make. "I'll come to that" replied. But he didn't.

Even when they have deigned to write down some ideas, political centrists have ignored such issues. Pretty much the only reference to economic policy in Change UK's launch manifesto was to the need for the government's "responsibility to ensure the sound stewardship of taxpayer's money", as if we were still in a world of bond vigilantes. And Chris Leslie's Centre Ground paper (pdf) made almost no reference to the fact that the financial crisis and subsequent stagnation in real wages and productivity requires centrists to re-assess the economic idea they had in the 90s.

Instead of intellectual analysis, centrists offer us two things. One is pure retail politics, accommodating itself to a selective perception of what voters want: Mandelson - once a Remainer - for example now thinks Labour must embrace "Brexit values" without also noting that higher taxes on the rich and more nationalization are also popular. Among its many flaws - among which is that this would alienate lots of Labour voters - this ignores the fact that public opinion is changeable: Brexit, for example, moved from being the obsession of a few cranks to the dominant issue in politics as a result of right-wing campaigning and economic stagnation. Taken opinion as given thus means skating to where the puck is rather than to where it is going.

A second strand of centrism is more common among media centrists. Take for example Jonathan Freedland's anger at Johnson's corruption. When given the choice between Johnson and the alternative centrists like Freedland ducked out, failing to appreciate that real life is sometimes a choice of the lesser of two evils. In this sense, centrism is a form of identity politics - an urge for what Richard Sennett called a purified identity which leads to a whine about "why can't you all be sane, rational and honest like ME?"

Now, in saying this I'm not damning all centrists. If we look outside the political-media circle we can find signs of intelligent life such as in Radix or in Sam Bowman and Stian Westlake's work. Much of this, however, underplays the class problem - of how to build support for policies such as land taxes or tougher competition policy in the face of hostility from rentiers.

That's a separate argument, though. The fact is that even where centrists do have good ideas these have not (yet?) found their way into the political centre.

Hence Labour's problem right now. Whilst people will vote for something, even if it's lousy, they don't often vote for nothing. The vacuity of the centre has left Labour with a clapped out leadership bereft of ideas without a vision or a coherent message. As Grace says: "Labour has a choice to make: socialism or Pasokification."

Of course, it has not always been this way. It's easy to forget that New Labour actually had an intelligent and coherent - if flawed - economic narrative. The challenge for the Labour right is to either discover a version of that narrative fit for the 2020s, or to remain the braindead quislings of rentier capital.