Waiting for the Etonians, By Nick Cohen

What are political columnists for? As the sales figures of the dailies and Sundays decline, editors of the quondam broadsheets try to poach readers by hiring this or that opinionator out on the rim of house politics. At the same time, as world news becomes more expensive to collect, editors fill pages with brief articles whose purpose is less to provide the full, prompt and accurate information on matters of public importance, and more to inflame a passing spasm of self-righteous rage on a subject about which readers already hold unreflective certainties.

Nick Cohen is a busy, decent and talkative member of this group. In his earlier book, What's Left?, he made into his signature theme the poverty, confusion and dereliction of Old Left politics. He spoke not only as a a custodian of canonical left-wing values, but also as the scourge of sentimental unreason, anti-Americanism, and the refusal to name for what they are kleptocratic black dictators, Islamist murderers and antique class injustices.

It is a tricky act to bring off, and Grub Street doesn't provide as much room as it did to spread your argument. Cohen has here reprinted almost everything in his file since 2005. But the relations of production mean that some of the articles are sketchy to a fault, and others too transitory to pass muster. A scandalised piece on Damien Hirst's jewelled skull is no doubt a deathly sign of the times, but Cohen's sally into the kitchen of The Gay Hussar is just embarrassing.

It is a consequence of how columnists have to overwork and underwrite that much of what they say is so high-pitched but so unsubstantiated. Tiny parodic figures in opposition to their views do duty for sharp analysis and blunt rebuttal. Cohen has to keep his microphone turned up deafeningly high in order to ratify his unquenchable spirit of outrage. The casualty is rational argument - the more so since Cohen's best targets so urgently need rational demolition.

It is true, as he says, that Islam retains in parts of its inheritance horrible oppressions. He is right that everywhere the gibberish of the therapeutic has dissolved moral language into a sentimental gruel. Above all it is a source of national disgrace that the super-rich have so got away with our and their fortunes, and have created for their perpetuation the well-tailored dummies in the Tory Party.

The hole in the centre of this scrapbook is left by grown-up economics. It is much to Cohen's credit that in March 2007 he published a piece on that giveaway neologism, "sub-prime lending". But he has missed the chance of a lifetime to tie his just strictures on the failure of an equitable political economy to the incipient Depression.

In Cohen's parent newspaper, Will Hutton is taking that opportunity each week. In these pages, Jeremy Warner is doing likewise. Social democracy has plenty of life in it; nor is the country bankrupt, as Cohen baldly announces.

I'm glad nonetheless to have this book, pleased to see social class put back at the centre of political thought. But if a book like this is to be some use, this clever and vigorous columnist needs to win time and room from his editor to think more equably, more historically. Also, he needs to get out of London and visit Wigan Pier; to rediscover his faith in what Wordsworth called "certain inherent and indestructible qualities of the human mind".

Fred Inglis's books include 'People's Witness: the journalist in modern politics'