Unhitched: the Trial of Christopher Hitchens, By Richard Seymour

Barely a year after his death by cancer of the oesophagus born with striking stoicism and, as his friend Ian McEwan put it, much consoled by his unbelief, Christopher Hitchens is here arraigned and sentenced for apostasy: for joining the company of the "hard right", the American warmongers, the "Jeffersonian imperialists". Not only that; Richard Seymour traces what he claims to be the seeds of treason and betrayal long germinating in Hitchens's colossal oeuvre.

It is a truth universally acknowledged that the far left never forgives defection, nor even mild criticism of its most admired spokespeople. Seymour fairly dances on the fresh grave, convicting the traitor to his own satisfaction not only of friendship with George W Bush's henchmen, but also of not-so-secret power-worship, a long-lurking ratification of the necessities of imperialism, explicit support of Thatcherism, as well as a philistinism in literature best illustrated by an avowed regard for the poetry of Rudyard Kipling.

Seymour is certainly master of the records; he knows the work closely and cites it scrupulously. But his headlong, foam-flecked interpretation, voiced in a manner recklessly close to Hitchens's own but without the grace, the wit, the tearing high spirits and the faultless ear for the fall of a cadence of his great original, becomes merely tedious, repetitive and unconvincing.

Hitchens was far too subtle a historian as well as too boisterous and brutal a controversialist to be accused of being "predictable as hell" or "a sentimentalist" with an approach to politics "profoundly visceral and instinctual". One can only recoil in disgust from someone who first accuses his subject of always seeking to make his enemies appear "unprincipled... mediocre and physically repulsive mountebanks", and who then, smirking, writes "in fairness, Hitchens might have struggled if those standards were applied to him".

Fairness, we soggy liberals' catch-all value, is nowhere in evidence in this shoddy little book. It is no surprise that its author delayed his malediction until his victim was safely out of earshot. He ignores the prodigious prodigality of Hitchens's writing: getting on for 10,000 pages of political reporting and historical analysis, literary criticism, theological polemic, edited collections, autobiography, and (a neglected but necessary genre) elegies for friends and old comrades. Seymour accuses him of dereliction of duty in this regard, but Hitchens is surely exceptional in the affection and loyalty he shows in his books towards a remarkable quintet of lifelong friends: Ian McEwan, Martin Amis, James Fenton, Salman Rushdie, Edward Said.

Nor is any mention made by our prosecutor of Hitchens's courage and daring, his devotion to professional duty as well as his crazy adventurousness. That took him to Romania as Ceausescu fell in a welter of bloodshed, to Kurdistan to view the hideous remains of Saddam Hussein's repression, to Nicaragua to plot the passage of Ronald Reagan's lies from public obfuscation about the Contras to their murderous actuality in the rainforest, to the innumerable battlefields of "the long peace" enjoyed by the West. This is the man who rooted out the immortal story of Anthony Eden, on the way to war in Suez, throwing a large, full inkpot at his strategic advisor, Basil Liddell Hart, who then responded by cramming the waste-paper basket over the PM's head.

In a marvellous essay on Paul Scott's tetralogy, The Jewel in the Crown, with its threnody over the Raj, Hitchens singles out Scott's judgement that "here in Ranpur, the British came to the end of themselves as they were". Hitchens accepted Scott's stony certainty. Across the 30 years since that essay, he also concluded, as any rational person must, that although Marx's diagnosis was clinching, there was absolutely no foreseeable prospect of the promises of socialism being kept. With the kind of mad certainty which so characterised him, he took the oath of allegiance to the Stars and Stripes, and signed on as propagandist for the war on terror.

Seymour is right to say that this melodramatic move was indeed characteristic. He is wrong and malicious, let alone poisonous in his use of casual innuendo, to try to turn such a public gesture into a consequence of deviousness everywhere discoverable in the conduct of the man, further contaminated by plagiarism, "terrific fibbing" and a zeal to make lots of money.

Seymour's own, wholly undefended pieties, which merely recite the litany of the left church, reassure him of Hitchens's shiftiness, of his keeping bad company, of his mendacity, treachery and worse. But it was once a precept of the left that bringing down any tyrant was a Good Thing. When the Iraq war turned into the public murder of Shia by Sunni, the occasion was ready-made for Hitchens's version of what Seymour calls his "theophobia". Alternatively, you might say that Hitchens was perfectly consistent. This little book is 134 pages long. The author shouldn't have done it. It is paltry and it is trivially abusive. Its subject was as eloquent, cultivated, exuberant, unstoppable, sheerly gigantic a journalist as British or American politics has known since George Orwell or Walter Lippmann. He can't be cursed into obscurity.

Fred Inglis's books include 'People's Witness: the Journalist in Modern Politics' (Yale University Press)